mirror of
https://github.com/RetroDECK/ES-DE.git
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1948 lines
62 KiB
C
1948 lines
62 KiB
C
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/***************************************************************************/
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/* */
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/* ftstroke.c */
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/* */
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/* FreeType path stroker (body). */
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/* */
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/* Copyright 2002-2006, 2008-2011, 2013 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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/* */
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/* This file is part of the FreeType project, and may only be used, */
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/* modified, and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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#include "plutovg-ft-stroker.h"
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#include "plutovg-ft-math.h"
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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/*************************************************************************/
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/*************************************************************************/
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/***** *****/
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/***** BEZIER COMPUTATIONS *****/
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/***** *****/
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/*************************************************************************/
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/*************************************************************************/
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#define PVG_FT_SMALL_CONIC_THRESHOLD (PVG_FT_ANGLE_PI / 6)
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#define PVG_FT_SMALL_CUBIC_THRESHOLD (PVG_FT_ANGLE_PI / 8)
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#define PVG_FT_EPSILON 2
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#define PVG_FT_IS_SMALL(x) ((x) > -PVG_FT_EPSILON && (x) < PVG_FT_EPSILON)
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static PVG_FT_Pos ft_pos_abs(PVG_FT_Pos x)
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{
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return x >= 0 ? x : -x;
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}
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static void ft_conic_split(PVG_FT_Vector* base)
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{
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PVG_FT_Pos a, b;
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base[4].x = base[2].x;
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a = base[0].x + base[1].x;
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b = base[1].x + base[2].x;
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base[3].x = b >> 1;
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base[2].x = ( a + b ) >> 2;
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base[1].x = a >> 1;
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base[4].y = base[2].y;
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a = base[0].y + base[1].y;
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b = base[1].y + base[2].y;
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base[3].y = b >> 1;
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base[2].y = ( a + b ) >> 2;
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base[1].y = a >> 1;
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}
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static PVG_FT_Bool ft_conic_is_small_enough(PVG_FT_Vector* base,
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PVG_FT_Angle* angle_in,
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PVG_FT_Angle* angle_out)
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{
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PVG_FT_Vector d1, d2;
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PVG_FT_Angle theta;
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PVG_FT_Int close1, close2;
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d1.x = base[1].x - base[2].x;
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d1.y = base[1].y - base[2].y;
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d2.x = base[0].x - base[1].x;
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d2.y = base[0].y - base[1].y;
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close1 = PVG_FT_IS_SMALL(d1.x) && PVG_FT_IS_SMALL(d1.y);
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close2 = PVG_FT_IS_SMALL(d2.x) && PVG_FT_IS_SMALL(d2.y);
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if (close1) {
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if (close2) {
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/* basically a point; */
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/* do nothing to retain original direction */
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} else {
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*angle_in = *angle_out = PVG_FT_Atan2(d2.x, d2.y);
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}
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} else /* !close1 */
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{
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if (close2) {
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*angle_in = *angle_out = PVG_FT_Atan2(d1.x, d1.y);
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} else {
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*angle_in = PVG_FT_Atan2(d1.x, d1.y);
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*angle_out = PVG_FT_Atan2(d2.x, d2.y);
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}
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}
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theta = ft_pos_abs(PVG_FT_Angle_Diff(*angle_in, *angle_out));
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return PVG_FT_BOOL(theta < PVG_FT_SMALL_CONIC_THRESHOLD);
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}
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static void ft_cubic_split(PVG_FT_Vector* base)
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{
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PVG_FT_Pos a, b, c;
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base[6].x = base[3].x;
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a = base[0].x + base[1].x;
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b = base[1].x + base[2].x;
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c = base[2].x + base[3].x;
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base[5].x = c >> 1;
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c += b;
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base[4].x = c >> 2;
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base[1].x = a >> 1;
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a += b;
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base[2].x = a >> 2;
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base[3].x = ( a + c ) >> 3;
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base[6].y = base[3].y;
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a = base[0].y + base[1].y;
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b = base[1].y + base[2].y;
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c = base[2].y + base[3].y;
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base[5].y = c >> 1;
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c += b;
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base[4].y = c >> 2;
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base[1].y = a >> 1;
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a += b;
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base[2].y = a >> 2;
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base[3].y = ( a + c ) >> 3;
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}
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/* Return the average of `angle1' and `angle2'. */
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/* This gives correct result even if `angle1' and `angle2' */
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/* have opposite signs. */
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static PVG_FT_Angle ft_angle_mean(PVG_FT_Angle angle1, PVG_FT_Angle angle2)
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{
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return angle1 + PVG_FT_Angle_Diff(angle1, angle2) / 2;
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}
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static PVG_FT_Bool ft_cubic_is_small_enough(PVG_FT_Vector* base,
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PVG_FT_Angle* angle_in,
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PVG_FT_Angle* angle_mid,
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PVG_FT_Angle* angle_out)
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{
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PVG_FT_Vector d1, d2, d3;
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PVG_FT_Angle theta1, theta2;
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PVG_FT_Int close1, close2, close3;
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d1.x = base[2].x - base[3].x;
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d1.y = base[2].y - base[3].y;
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d2.x = base[1].x - base[2].x;
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d2.y = base[1].y - base[2].y;
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d3.x = base[0].x - base[1].x;
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d3.y = base[0].y - base[1].y;
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close1 = PVG_FT_IS_SMALL(d1.x) && PVG_FT_IS_SMALL(d1.y);
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close2 = PVG_FT_IS_SMALL(d2.x) && PVG_FT_IS_SMALL(d2.y);
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close3 = PVG_FT_IS_SMALL(d3.x) && PVG_FT_IS_SMALL(d3.y);
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if (close1) {
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if (close2) {
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if (close3) {
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/* basically a point; */
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/* do nothing to retain original direction */
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} else /* !close3 */
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{
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*angle_in = *angle_mid = *angle_out = PVG_FT_Atan2(d3.x, d3.y);
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}
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} else /* !close2 */
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{
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if (close3) {
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*angle_in = *angle_mid = *angle_out = PVG_FT_Atan2(d2.x, d2.y);
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} else /* !close3 */
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{
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*angle_in = *angle_mid = PVG_FT_Atan2(d2.x, d2.y);
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*angle_out = PVG_FT_Atan2(d3.x, d3.y);
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}
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}
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} else /* !close1 */
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{
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if (close2) {
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if (close3) {
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*angle_in = *angle_mid = *angle_out = PVG_FT_Atan2(d1.x, d1.y);
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} else /* !close3 */
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{
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*angle_in = PVG_FT_Atan2(d1.x, d1.y);
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*angle_out = PVG_FT_Atan2(d3.x, d3.y);
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*angle_mid = ft_angle_mean(*angle_in, *angle_out);
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}
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} else /* !close2 */
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{
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if (close3) {
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*angle_in = PVG_FT_Atan2(d1.x, d1.y);
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*angle_mid = *angle_out = PVG_FT_Atan2(d2.x, d2.y);
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} else /* !close3 */
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{
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*angle_in = PVG_FT_Atan2(d1.x, d1.y);
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*angle_mid = PVG_FT_Atan2(d2.x, d2.y);
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*angle_out = PVG_FT_Atan2(d3.x, d3.y);
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}
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}
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}
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theta1 = ft_pos_abs(PVG_FT_Angle_Diff(*angle_in, *angle_mid));
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theta2 = ft_pos_abs(PVG_FT_Angle_Diff(*angle_mid, *angle_out));
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return PVG_FT_BOOL(theta1 < PVG_FT_SMALL_CUBIC_THRESHOLD &&
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theta2 < PVG_FT_SMALL_CUBIC_THRESHOLD);
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}
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/*************************************************************************/
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/*************************************************************************/
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/***** *****/
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/***** STROKE BORDERS *****/
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/***** *****/
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/*************************************************************************/
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/*************************************************************************/
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typedef enum PVG_FT_StrokeTags_ {
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PVG_FT_STROKE_TAG_ON = 1, /* on-curve point */
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PVG_FT_STROKE_TAG_CUBIC = 2, /* cubic off-point */
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PVG_FT_STROKE_TAG_BEGIN = 4, /* sub-path start */
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PVG_FT_STROKE_TAG_END = 8 /* sub-path end */
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} PVG_FT_StrokeTags;
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#define PVG_FT_STROKE_TAG_BEGIN_END \
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(PVG_FT_STROKE_TAG_BEGIN | PVG_FT_STROKE_TAG_END)
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typedef struct PVG_FT_StrokeBorderRec_ {
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PVG_FT_UInt num_points;
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PVG_FT_UInt max_points;
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PVG_FT_Vector* points;
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PVG_FT_Byte* tags;
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PVG_FT_Bool movable; /* TRUE for ends of lineto borders */
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PVG_FT_Int start; /* index of current sub-path start point */
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PVG_FT_Bool valid;
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} PVG_FT_StrokeBorderRec, *PVG_FT_StrokeBorder;
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PVG_FT_Error PVG_FT_Outline_Check(PVG_FT_Outline* outline)
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{
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if (outline) {
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PVG_FT_Int n_points = outline->n_points;
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PVG_FT_Int n_contours = outline->n_contours;
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PVG_FT_Int end0, end;
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PVG_FT_Int n;
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/* empty glyph? */
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if (n_points == 0 && n_contours == 0) return 0;
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/* check point and contour counts */
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if (n_points <= 0 || n_contours <= 0) goto Bad;
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end0 = end = -1;
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for (n = 0; n < n_contours; n++) {
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end = outline->contours[n];
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/* note that we don't accept empty contours */
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if (end <= end0 || end >= n_points) goto Bad;
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end0 = end;
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}
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if (end != n_points - 1) goto Bad;
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/* XXX: check the tags array */
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return 0;
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}
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Bad:
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return -1; // PVG_FT_THROW( Invalid_Argument );
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}
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void PVG_FT_Outline_Get_CBox(const PVG_FT_Outline* outline, PVG_FT_BBox* acbox)
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{
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PVG_FT_Pos xMin, yMin, xMax, yMax;
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if (outline && acbox) {
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if (outline->n_points == 0) {
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xMin = 0;
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yMin = 0;
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xMax = 0;
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yMax = 0;
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} else {
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PVG_FT_Vector* vec = outline->points;
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PVG_FT_Vector* limit = vec + outline->n_points;
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xMin = xMax = vec->x;
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yMin = yMax = vec->y;
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vec++;
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for (; vec < limit; vec++) {
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PVG_FT_Pos x, y;
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x = vec->x;
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if (x < xMin) xMin = x;
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if (x > xMax) xMax = x;
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y = vec->y;
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if (y < yMin) yMin = y;
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if (y > yMax) yMax = y;
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}
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}
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acbox->xMin = xMin;
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acbox->xMax = xMax;
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acbox->yMin = yMin;
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acbox->yMax = yMax;
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}
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}
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static PVG_FT_Error ft_stroke_border_grow(PVG_FT_StrokeBorder border,
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PVG_FT_UInt new_points)
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{
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PVG_FT_UInt old_max = border->max_points;
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PVG_FT_UInt new_max = border->num_points + new_points;
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PVG_FT_Error error = 0;
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if (new_max > old_max) {
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PVG_FT_UInt cur_max = old_max;
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while (cur_max < new_max) cur_max += (cur_max >> 1) + 16;
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border->points = (PVG_FT_Vector*)realloc(border->points,
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cur_max * sizeof(PVG_FT_Vector));
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border->tags =
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(PVG_FT_Byte*)realloc(border->tags, cur_max * sizeof(PVG_FT_Byte));
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if (!border->points || !border->tags) goto Exit;
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border->max_points = cur_max;
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}
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Exit:
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return error;
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}
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static void ft_stroke_border_close(PVG_FT_StrokeBorder border,
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PVG_FT_Bool reverse)
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{
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PVG_FT_UInt start = border->start;
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PVG_FT_UInt count = border->num_points;
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assert(border->start >= 0);
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/* don't record empty paths! */
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if (count <= start + 1U)
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border->num_points = start;
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else {
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/* copy the last point to the start of this sub-path, since */
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/* it contains the `adjusted' starting coordinates */
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border->num_points = --count;
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border->points[start] = border->points[count];
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border->tags[start] = border->tags[count];
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if (reverse) {
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/* reverse the points */
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{
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PVG_FT_Vector* vec1 = border->points + start + 1;
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PVG_FT_Vector* vec2 = border->points + count - 1;
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for (; vec1 < vec2; vec1++, vec2--) {
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PVG_FT_Vector tmp;
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tmp = *vec1;
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*vec1 = *vec2;
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*vec2 = tmp;
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}
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}
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/* then the tags */
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{
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PVG_FT_Byte* tag1 = border->tags + start + 1;
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PVG_FT_Byte* tag2 = border->tags + count - 1;
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for (; tag1 < tag2; tag1++, tag2--) {
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PVG_FT_Byte tmp;
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tmp = *tag1;
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*tag1 = *tag2;
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*tag2 = tmp;
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}
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}
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}
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border->tags[start] |= PVG_FT_STROKE_TAG_BEGIN;
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border->tags[count - 1] |= PVG_FT_STROKE_TAG_END;
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}
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border->start = -1;
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border->movable = FALSE;
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}
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static PVG_FT_Error ft_stroke_border_lineto(PVG_FT_StrokeBorder border,
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PVG_FT_Vector* to, PVG_FT_Bool movable)
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{
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PVG_FT_Error error = 0;
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assert(border->start >= 0);
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if (border->movable) {
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/* move last point */
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border->points[border->num_points - 1] = *to;
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} else {
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/* don't add zero-length lineto */
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if (border->num_points > 0 &&
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PVG_FT_IS_SMALL(border->points[border->num_points - 1].x - to->x) &&
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PVG_FT_IS_SMALL(border->points[border->num_points - 1].y - to->y))
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return error;
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/* add one point */
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error = ft_stroke_border_grow(border, 1);
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if (!error) {
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PVG_FT_Vector* vec = border->points + border->num_points;
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PVG_FT_Byte* tag = border->tags + border->num_points;
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vec[0] = *to;
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tag[0] = PVG_FT_STROKE_TAG_ON;
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border->num_points += 1;
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}
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}
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border->movable = movable;
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return error;
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}
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static PVG_FT_Error ft_stroke_border_conicto(PVG_FT_StrokeBorder border,
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PVG_FT_Vector* control,
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PVG_FT_Vector* to)
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{
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PVG_FT_Error error;
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assert(border->start >= 0);
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error = ft_stroke_border_grow(border, 2);
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if (!error) {
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PVG_FT_Vector* vec = border->points + border->num_points;
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PVG_FT_Byte* tag = border->tags + border->num_points;
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vec[0] = *control;
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vec[1] = *to;
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tag[0] = 0;
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tag[1] = PVG_FT_STROKE_TAG_ON;
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border->num_points += 2;
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}
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border->movable = FALSE;
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return error;
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}
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static PVG_FT_Error ft_stroke_border_cubicto(PVG_FT_StrokeBorder border,
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PVG_FT_Vector* control1,
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PVG_FT_Vector* control2,
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PVG_FT_Vector* to)
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{
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PVG_FT_Error error;
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assert(border->start >= 0);
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error = ft_stroke_border_grow(border, 3);
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if (!error) {
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PVG_FT_Vector* vec = border->points + border->num_points;
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PVG_FT_Byte* tag = border->tags + border->num_points;
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vec[0] = *control1;
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vec[1] = *control2;
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vec[2] = *to;
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tag[0] = PVG_FT_STROKE_TAG_CUBIC;
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tag[1] = PVG_FT_STROKE_TAG_CUBIC;
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tag[2] = PVG_FT_STROKE_TAG_ON;
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border->num_points += 3;
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}
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border->movable = FALSE;
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return error;
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}
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#define PVG_FT_ARC_CUBIC_ANGLE (PVG_FT_ANGLE_PI / 2)
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static PVG_FT_Error
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ft_stroke_border_arcto( PVG_FT_StrokeBorder border,
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PVG_FT_Vector* center,
|
|
PVG_FT_Fixed radius,
|
|
PVG_FT_Angle angle_start,
|
|
PVG_FT_Angle angle_diff )
|
|
{
|
|
PVG_FT_Fixed coef;
|
|
PVG_FT_Vector a0, a1, a2, a3;
|
|
PVG_FT_Int i, arcs = 1;
|
|
PVG_FT_Error error = 0;
|
|
|
|
|
|
/* number of cubic arcs to draw */
|
|
while ( angle_diff > PVG_FT_ARC_CUBIC_ANGLE * arcs ||
|
|
-angle_diff > PVG_FT_ARC_CUBIC_ANGLE * arcs )
|
|
arcs++;
|
|
|
|
/* control tangents */
|
|
coef = PVG_FT_Tan( angle_diff / ( 4 * arcs ) );
|
|
coef += coef / 3;
|
|
|
|
/* compute start and first control point */
|
|
PVG_FT_Vector_From_Polar( &a0, radius, angle_start );
|
|
a1.x = PVG_FT_MulFix( -a0.y, coef );
|
|
a1.y = PVG_FT_MulFix( a0.x, coef );
|
|
|
|
a0.x += center->x;
|
|
a0.y += center->y;
|
|
a1.x += a0.x;
|
|
a1.y += a0.y;
|
|
|
|
for ( i = 1; i <= arcs; i++ )
|
|
{
|
|
/* compute end and second control point */
|
|
PVG_FT_Vector_From_Polar( &a3, radius,
|
|
angle_start + i * angle_diff / arcs );
|
|
a2.x = PVG_FT_MulFix( a3.y, coef );
|
|
a2.y = PVG_FT_MulFix( -a3.x, coef );
|
|
|
|
a3.x += center->x;
|
|
a3.y += center->y;
|
|
a2.x += a3.x;
|
|
a2.y += a3.y;
|
|
|
|
/* add cubic arc */
|
|
error = ft_stroke_border_cubicto( border, &a1, &a2, &a3 );
|
|
if ( error )
|
|
break;
|
|
|
|
/* a0 = a3; */
|
|
a1.x = a3.x - a2.x + a3.x;
|
|
a1.y = a3.y - a2.y + a3.y;
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
static PVG_FT_Error ft_stroke_border_moveto(PVG_FT_StrokeBorder border,
|
|
PVG_FT_Vector* to)
|
|
{
|
|
/* close current open path if any ? */
|
|
if (border->start >= 0) ft_stroke_border_close(border, FALSE);
|
|
|
|
border->start = border->num_points;
|
|
border->movable = FALSE;
|
|
|
|
return ft_stroke_border_lineto(border, to, FALSE);
|
|
}
|
|
|
|
static void ft_stroke_border_init(PVG_FT_StrokeBorder border)
|
|
{
|
|
border->points = NULL;
|
|
border->tags = NULL;
|
|
|
|
border->num_points = 0;
|
|
border->max_points = 0;
|
|
border->start = -1;
|
|
border->valid = FALSE;
|
|
}
|
|
|
|
static void ft_stroke_border_reset(PVG_FT_StrokeBorder border)
|
|
{
|
|
border->num_points = 0;
|
|
border->start = -1;
|
|
border->valid = FALSE;
|
|
}
|
|
|
|
static void ft_stroke_border_done(PVG_FT_StrokeBorder border)
|
|
{
|
|
free(border->points);
|
|
free(border->tags);
|
|
|
|
border->num_points = 0;
|
|
border->max_points = 0;
|
|
border->start = -1;
|
|
border->valid = FALSE;
|
|
}
|
|
|
|
static PVG_FT_Error ft_stroke_border_get_counts(PVG_FT_StrokeBorder border,
|
|
PVG_FT_UInt* anum_points,
|
|
PVG_FT_UInt* anum_contours)
|
|
{
|
|
PVG_FT_Error error = 0;
|
|
PVG_FT_UInt num_points = 0;
|
|
PVG_FT_UInt num_contours = 0;
|
|
|
|
PVG_FT_UInt count = border->num_points;
|
|
PVG_FT_Vector* point = border->points;
|
|
PVG_FT_Byte* tags = border->tags;
|
|
PVG_FT_Int in_contour = 0;
|
|
|
|
for (; count > 0; count--, num_points++, point++, tags++) {
|
|
if (tags[0] & PVG_FT_STROKE_TAG_BEGIN) {
|
|
if (in_contour != 0) goto Fail;
|
|
|
|
in_contour = 1;
|
|
} else if (in_contour == 0)
|
|
goto Fail;
|
|
|
|
if (tags[0] & PVG_FT_STROKE_TAG_END) {
|
|
in_contour = 0;
|
|
num_contours++;
|
|
}
|
|
}
|
|
|
|
if (in_contour != 0) goto Fail;
|
|
|
|
border->valid = TRUE;
|
|
|
|
Exit:
|
|
*anum_points = num_points;
|
|
*anum_contours = num_contours;
|
|
return error;
|
|
|
|
Fail:
|
|
num_points = 0;
|
|
num_contours = 0;
|
|
goto Exit;
|
|
}
|
|
|
|
static void ft_stroke_border_export(PVG_FT_StrokeBorder border,
|
|
PVG_FT_Outline* outline)
|
|
{
|
|
/* copy point locations */
|
|
if (outline->points != NULL && border->points != NULL)
|
|
memcpy(outline->points + outline->n_points, border->points,
|
|
border->num_points * sizeof(PVG_FT_Vector));
|
|
|
|
/* copy tags */
|
|
if (outline->tags)
|
|
{
|
|
PVG_FT_UInt count = border->num_points;
|
|
PVG_FT_Byte* read = border->tags;
|
|
PVG_FT_Byte* write = (PVG_FT_Byte*)outline->tags + outline->n_points;
|
|
|
|
for (; count > 0; count--, read++, write++) {
|
|
if (*read & PVG_FT_STROKE_TAG_ON)
|
|
*write = PVG_FT_CURVE_TAG_ON;
|
|
else if (*read & PVG_FT_STROKE_TAG_CUBIC)
|
|
*write = PVG_FT_CURVE_TAG_CUBIC;
|
|
else
|
|
*write = PVG_FT_CURVE_TAG_CONIC;
|
|
}
|
|
}
|
|
|
|
/* copy contours */
|
|
if (outline->contours)
|
|
{
|
|
PVG_FT_UInt count = border->num_points;
|
|
PVG_FT_Byte* tags = border->tags;
|
|
PVG_FT_Int* write = outline->contours + outline->n_contours;
|
|
PVG_FT_Int idx = (PVG_FT_Int)outline->n_points;
|
|
|
|
for (; count > 0; count--, tags++, idx++) {
|
|
if (*tags & PVG_FT_STROKE_TAG_END) {
|
|
*write++ = idx;
|
|
outline->n_contours++;
|
|
}
|
|
}
|
|
}
|
|
|
|
outline->n_points = (int)(outline->n_points + border->num_points);
|
|
|
|
assert(PVG_FT_Outline_Check(outline) == 0);
|
|
}
|
|
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
/***** *****/
|
|
/***** STROKER *****/
|
|
/***** *****/
|
|
/*************************************************************************/
|
|
/*************************************************************************/
|
|
|
|
#define PVG_FT_SIDE_TO_ROTATE(s) (PVG_FT_ANGLE_PI2 - (s)*PVG_FT_ANGLE_PI)
|
|
|
|
typedef struct PVG_FT_StrokerRec_ {
|
|
PVG_FT_Angle angle_in; /* direction into curr join */
|
|
PVG_FT_Angle angle_out; /* direction out of join */
|
|
PVG_FT_Vector center; /* current position */
|
|
PVG_FT_Fixed line_length; /* length of last lineto */
|
|
PVG_FT_Bool first_point; /* is this the start? */
|
|
PVG_FT_Bool subpath_open; /* is the subpath open? */
|
|
PVG_FT_Angle subpath_angle; /* subpath start direction */
|
|
PVG_FT_Vector subpath_start; /* subpath start position */
|
|
PVG_FT_Fixed subpath_line_length; /* subpath start lineto len */
|
|
PVG_FT_Bool handle_wide_strokes; /* use wide strokes logic? */
|
|
|
|
PVG_FT_Stroker_LineCap line_cap;
|
|
PVG_FT_Stroker_LineJoin line_join;
|
|
PVG_FT_Stroker_LineJoin line_join_saved;
|
|
PVG_FT_Fixed miter_limit;
|
|
PVG_FT_Fixed radius;
|
|
|
|
PVG_FT_StrokeBorderRec borders[2];
|
|
} PVG_FT_StrokerRec;
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
PVG_FT_Error PVG_FT_Stroker_New(PVG_FT_Stroker* astroker)
|
|
{
|
|
PVG_FT_Error error = 0; /* assigned in PVG_FT_NEW */
|
|
PVG_FT_Stroker stroker = NULL;
|
|
|
|
stroker = (PVG_FT_StrokerRec*)calloc(1, sizeof(PVG_FT_StrokerRec));
|
|
if (stroker) {
|
|
ft_stroke_border_init(&stroker->borders[0]);
|
|
ft_stroke_border_init(&stroker->borders[1]);
|
|
}
|
|
|
|
*astroker = stroker;
|
|
|
|
return error;
|
|
}
|
|
|
|
void PVG_FT_Stroker_Rewind(PVG_FT_Stroker stroker)
|
|
{
|
|
if (stroker) {
|
|
ft_stroke_border_reset(&stroker->borders[0]);
|
|
ft_stroke_border_reset(&stroker->borders[1]);
|
|
}
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
void PVG_FT_Stroker_Set(PVG_FT_Stroker stroker, PVG_FT_Fixed radius,
|
|
PVG_FT_Stroker_LineCap line_cap,
|
|
PVG_FT_Stroker_LineJoin line_join,
|
|
PVG_FT_Fixed miter_limit)
|
|
{
|
|
stroker->radius = radius;
|
|
stroker->line_cap = line_cap;
|
|
stroker->line_join = line_join;
|
|
stroker->miter_limit = miter_limit;
|
|
|
|
/* ensure miter limit has sensible value */
|
|
if (stroker->miter_limit < 0x10000) stroker->miter_limit = 0x10000;
|
|
|
|
/* save line join style: */
|
|
/* line join style can be temporarily changed when stroking curves */
|
|
stroker->line_join_saved = line_join;
|
|
|
|
PVG_FT_Stroker_Rewind(stroker);
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
void PVG_FT_Stroker_Done(PVG_FT_Stroker stroker)
|
|
{
|
|
if (stroker) {
|
|
ft_stroke_border_done(&stroker->borders[0]);
|
|
ft_stroke_border_done(&stroker->borders[1]);
|
|
|
|
free(stroker);
|
|
}
|
|
}
|
|
|
|
/* create a circular arc at a corner or cap */
|
|
static PVG_FT_Error ft_stroker_arcto(PVG_FT_Stroker stroker, PVG_FT_Int side)
|
|
{
|
|
PVG_FT_Angle total, rotate;
|
|
PVG_FT_Fixed radius = stroker->radius;
|
|
PVG_FT_Error error = 0;
|
|
PVG_FT_StrokeBorder border = stroker->borders + side;
|
|
|
|
rotate = PVG_FT_SIDE_TO_ROTATE(side);
|
|
|
|
total = PVG_FT_Angle_Diff(stroker->angle_in, stroker->angle_out);
|
|
if (total == PVG_FT_ANGLE_PI) total = -rotate * 2;
|
|
|
|
error = ft_stroke_border_arcto(border, &stroker->center, radius,
|
|
stroker->angle_in + rotate, total);
|
|
border->movable = FALSE;
|
|
return error;
|
|
}
|
|
|
|
/* add a cap at the end of an opened path */
|
|
static PVG_FT_Error
|
|
ft_stroker_cap(PVG_FT_Stroker stroker,
|
|
PVG_FT_Angle angle,
|
|
PVG_FT_Int side)
|
|
{
|
|
PVG_FT_Error error = 0;
|
|
|
|
if (stroker->line_cap == PVG_FT_STROKER_LINECAP_ROUND)
|
|
{
|
|
/* add a round cap */
|
|
stroker->angle_in = angle;
|
|
stroker->angle_out = angle + PVG_FT_ANGLE_PI;
|
|
|
|
error = ft_stroker_arcto(stroker, side);
|
|
}
|
|
else
|
|
{
|
|
/* add a square or butt cap */
|
|
PVG_FT_Vector middle, delta;
|
|
PVG_FT_Fixed radius = stroker->radius;
|
|
PVG_FT_StrokeBorder border = stroker->borders + side;
|
|
|
|
/* compute middle point and first angle point */
|
|
PVG_FT_Vector_From_Polar( &middle, radius, angle );
|
|
delta.x = side ? middle.y : -middle.y;
|
|
delta.y = side ? -middle.x : middle.x;
|
|
|
|
if ( stroker->line_cap == PVG_FT_STROKER_LINECAP_SQUARE )
|
|
{
|
|
middle.x += stroker->center.x;
|
|
middle.y += stroker->center.y;
|
|
}
|
|
else /* PVG_FT_STROKER_LINECAP_BUTT */
|
|
{
|
|
middle.x = stroker->center.x;
|
|
middle.y = stroker->center.y;
|
|
}
|
|
|
|
delta.x += middle.x;
|
|
delta.y += middle.y;
|
|
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
if ( error )
|
|
goto Exit;
|
|
|
|
/* compute second angle point */
|
|
delta.x = middle.x - delta.x + middle.x;
|
|
delta.y = middle.y - delta.y + middle.y;
|
|
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
}
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* process an inside corner, i.e. compute intersection */
|
|
static PVG_FT_Error ft_stroker_inside(PVG_FT_Stroker stroker, PVG_FT_Int side,
|
|
PVG_FT_Fixed line_length)
|
|
{
|
|
PVG_FT_StrokeBorder border = stroker->borders + side;
|
|
PVG_FT_Angle phi, theta, rotate;
|
|
PVG_FT_Fixed length;
|
|
PVG_FT_Vector sigma = {0, 0};
|
|
PVG_FT_Vector delta;
|
|
PVG_FT_Error error = 0;
|
|
PVG_FT_Bool intersect; /* use intersection of lines? */
|
|
|
|
rotate = PVG_FT_SIDE_TO_ROTATE(side);
|
|
|
|
theta = PVG_FT_Angle_Diff(stroker->angle_in, stroker->angle_out) / 2;
|
|
|
|
/* Only intersect borders if between two lineto's and both */
|
|
/* lines are long enough (line_length is zero for curves). */
|
|
if (!border->movable || line_length == 0 ||
|
|
theta > 0x59C000 || theta < -0x59C000 )
|
|
intersect = FALSE;
|
|
else {
|
|
/* compute minimum required length of lines */
|
|
PVG_FT_Fixed min_length;
|
|
|
|
|
|
PVG_FT_Vector_Unit( &sigma, theta );
|
|
min_length =
|
|
ft_pos_abs( PVG_FT_MulDiv( stroker->radius, sigma.y, sigma.x ) );
|
|
|
|
intersect = PVG_FT_BOOL( min_length &&
|
|
stroker->line_length >= min_length &&
|
|
line_length >= min_length );
|
|
}
|
|
|
|
if (!intersect) {
|
|
PVG_FT_Vector_From_Polar(&delta, stroker->radius,
|
|
stroker->angle_out + rotate);
|
|
delta.x += stroker->center.x;
|
|
delta.y += stroker->center.y;
|
|
|
|
border->movable = FALSE;
|
|
} else {
|
|
/* compute median angle */
|
|
phi = stroker->angle_in + theta + rotate;
|
|
|
|
length = PVG_FT_DivFix( stroker->radius, sigma.x );
|
|
|
|
PVG_FT_Vector_From_Polar( &delta, length, phi );
|
|
delta.x += stroker->center.x;
|
|
delta.y += stroker->center.y;
|
|
}
|
|
|
|
error = ft_stroke_border_lineto(border, &delta, FALSE);
|
|
|
|
return error;
|
|
}
|
|
|
|
/* process an outside corner, i.e. compute bevel/miter/round */
|
|
static PVG_FT_Error
|
|
ft_stroker_outside( PVG_FT_Stroker stroker,
|
|
PVG_FT_Int side,
|
|
PVG_FT_Fixed line_length )
|
|
{
|
|
PVG_FT_StrokeBorder border = stroker->borders + side;
|
|
PVG_FT_Error error;
|
|
PVG_FT_Angle rotate;
|
|
|
|
|
|
if ( stroker->line_join == PVG_FT_STROKER_LINEJOIN_ROUND )
|
|
error = ft_stroker_arcto( stroker, side );
|
|
else
|
|
{
|
|
/* this is a mitered (pointed) or beveled (truncated) corner */
|
|
PVG_FT_Fixed radius = stroker->radius;
|
|
PVG_FT_Vector sigma = {0, 0};
|
|
PVG_FT_Angle theta = 0, phi = 0;
|
|
PVG_FT_Bool bevel, fixed_bevel;
|
|
|
|
|
|
rotate = PVG_FT_SIDE_TO_ROTATE( side );
|
|
|
|
bevel =
|
|
PVG_FT_BOOL( stroker->line_join == PVG_FT_STROKER_LINEJOIN_BEVEL );
|
|
|
|
fixed_bevel =
|
|
PVG_FT_BOOL( stroker->line_join != PVG_FT_STROKER_LINEJOIN_MITER_VARIABLE );
|
|
|
|
/* check miter limit first */
|
|
if ( !bevel )
|
|
{
|
|
theta = PVG_FT_Angle_Diff( stroker->angle_in, stroker->angle_out ) / 2;
|
|
|
|
if ( theta == PVG_FT_ANGLE_PI2 )
|
|
theta = -rotate;
|
|
|
|
phi = stroker->angle_in + theta + rotate;
|
|
|
|
PVG_FT_Vector_From_Polar( &sigma, stroker->miter_limit, theta );
|
|
|
|
/* is miter limit exceeded? */
|
|
if ( sigma.x < 0x10000L )
|
|
{
|
|
/* don't create variable bevels for very small deviations; */
|
|
/* FT_Sin(x) = 0 for x <= 57 */
|
|
if ( fixed_bevel || ft_pos_abs( theta ) > 57 )
|
|
bevel = TRUE;
|
|
}
|
|
}
|
|
|
|
if ( bevel ) /* this is a bevel (broken angle) */
|
|
{
|
|
if ( fixed_bevel )
|
|
{
|
|
/* the outer corners are simply joined together */
|
|
PVG_FT_Vector delta;
|
|
|
|
|
|
/* add bevel */
|
|
PVG_FT_Vector_From_Polar( &delta,
|
|
radius,
|
|
stroker->angle_out + rotate );
|
|
delta.x += stroker->center.x;
|
|
delta.y += stroker->center.y;
|
|
|
|
border->movable = FALSE;
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
}
|
|
else /* variable bevel or clipped miter */
|
|
{
|
|
/* the miter is truncated */
|
|
PVG_FT_Vector middle, delta;
|
|
PVG_FT_Fixed coef;
|
|
|
|
|
|
/* compute middle point and first angle point */
|
|
PVG_FT_Vector_From_Polar( &middle,
|
|
PVG_FT_MulFix( radius, stroker->miter_limit ),
|
|
phi );
|
|
|
|
coef = PVG_FT_DivFix( 0x10000L - sigma.x, sigma.y );
|
|
delta.x = PVG_FT_MulFix( middle.y, coef );
|
|
delta.y = PVG_FT_MulFix( -middle.x, coef );
|
|
|
|
middle.x += stroker->center.x;
|
|
middle.y += stroker->center.y;
|
|
delta.x += middle.x;
|
|
delta.y += middle.y;
|
|
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
if ( error )
|
|
goto Exit;
|
|
|
|
/* compute second angle point */
|
|
delta.x = middle.x - delta.x + middle.x;
|
|
delta.y = middle.y - delta.y + middle.y;
|
|
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
if ( error )
|
|
goto Exit;
|
|
|
|
/* finally, add an end point; only needed if not lineto */
|
|
/* (line_length is zero for curves) */
|
|
if ( line_length == 0 )
|
|
{
|
|
PVG_FT_Vector_From_Polar( &delta,
|
|
radius,
|
|
stroker->angle_out + rotate );
|
|
|
|
delta.x += stroker->center.x;
|
|
delta.y += stroker->center.y;
|
|
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
}
|
|
}
|
|
}
|
|
else /* this is a miter (intersection) */
|
|
{
|
|
PVG_FT_Fixed length;
|
|
PVG_FT_Vector delta;
|
|
|
|
|
|
length = PVG_FT_MulDiv( stroker->radius, stroker->miter_limit, sigma.x );
|
|
|
|
PVG_FT_Vector_From_Polar( &delta, length, phi );
|
|
delta.x += stroker->center.x;
|
|
delta.y += stroker->center.y;
|
|
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
if ( error )
|
|
goto Exit;
|
|
|
|
/* now add an end point; only needed if not lineto */
|
|
/* (line_length is zero for curves) */
|
|
if ( line_length == 0 )
|
|
{
|
|
PVG_FT_Vector_From_Polar( &delta,
|
|
stroker->radius,
|
|
stroker->angle_out + rotate );
|
|
delta.x += stroker->center.x;
|
|
delta.y += stroker->center.y;
|
|
|
|
error = ft_stroke_border_lineto( border, &delta, FALSE );
|
|
}
|
|
}
|
|
}
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
static PVG_FT_Error ft_stroker_process_corner(PVG_FT_Stroker stroker,
|
|
PVG_FT_Fixed line_length)
|
|
{
|
|
PVG_FT_Error error = 0;
|
|
PVG_FT_Angle turn;
|
|
PVG_FT_Int inside_side;
|
|
|
|
turn = PVG_FT_Angle_Diff(stroker->angle_in, stroker->angle_out);
|
|
|
|
/* no specific corner processing is required if the turn is 0 */
|
|
if (turn == 0) goto Exit;
|
|
|
|
/* when we turn to the right, the inside side is 0 */
|
|
inside_side = 0;
|
|
|
|
/* otherwise, the inside side is 1 */
|
|
if (turn < 0) inside_side = 1;
|
|
|
|
/* process the inside side */
|
|
error = ft_stroker_inside(stroker, inside_side, line_length);
|
|
if (error) goto Exit;
|
|
|
|
/* process the outside side */
|
|
error = ft_stroker_outside(stroker, 1 - inside_side, line_length);
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* add two points to the left and right borders corresponding to the */
|
|
/* start of the subpath */
|
|
static PVG_FT_Error ft_stroker_subpath_start(PVG_FT_Stroker stroker,
|
|
PVG_FT_Angle start_angle,
|
|
PVG_FT_Fixed line_length)
|
|
{
|
|
PVG_FT_Vector delta;
|
|
PVG_FT_Vector point;
|
|
PVG_FT_Error error;
|
|
PVG_FT_StrokeBorder border;
|
|
|
|
PVG_FT_Vector_From_Polar(&delta, stroker->radius,
|
|
start_angle + PVG_FT_ANGLE_PI2);
|
|
|
|
point.x = stroker->center.x + delta.x;
|
|
point.y = stroker->center.y + delta.y;
|
|
|
|
border = stroker->borders;
|
|
error = ft_stroke_border_moveto(border, &point);
|
|
if (error) goto Exit;
|
|
|
|
point.x = stroker->center.x - delta.x;
|
|
point.y = stroker->center.y - delta.y;
|
|
|
|
border++;
|
|
error = ft_stroke_border_moveto(border, &point);
|
|
|
|
/* save angle, position, and line length for last join */
|
|
/* (line_length is zero for curves) */
|
|
stroker->subpath_angle = start_angle;
|
|
stroker->first_point = FALSE;
|
|
stroker->subpath_line_length = line_length;
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
PVG_FT_Error PVG_FT_Stroker_LineTo(PVG_FT_Stroker stroker, PVG_FT_Vector* to)
|
|
{
|
|
PVG_FT_Error error = 0;
|
|
PVG_FT_StrokeBorder border;
|
|
PVG_FT_Vector delta;
|
|
PVG_FT_Angle angle;
|
|
PVG_FT_Int side;
|
|
PVG_FT_Fixed line_length;
|
|
|
|
delta.x = to->x - stroker->center.x;
|
|
delta.y = to->y - stroker->center.y;
|
|
|
|
/* a zero-length lineto is a no-op; avoid creating a spurious corner */
|
|
if (delta.x == 0 && delta.y == 0) goto Exit;
|
|
|
|
/* compute length of line */
|
|
line_length = PVG_FT_Vector_Length(&delta);
|
|
|
|
angle = PVG_FT_Atan2(delta.x, delta.y);
|
|
PVG_FT_Vector_From_Polar(&delta, stroker->radius, angle + PVG_FT_ANGLE_PI2);
|
|
|
|
/* process corner if necessary */
|
|
if (stroker->first_point) {
|
|
/* This is the first segment of a subpath. We need to */
|
|
/* add a point to each border at their respective starting */
|
|
/* point locations. */
|
|
error = ft_stroker_subpath_start(stroker, angle, line_length);
|
|
if (error) goto Exit;
|
|
} else {
|
|
/* process the current corner */
|
|
stroker->angle_out = angle;
|
|
error = ft_stroker_process_corner(stroker, line_length);
|
|
if (error) goto Exit;
|
|
}
|
|
|
|
/* now add a line segment to both the `inside' and `outside' paths */
|
|
for (border = stroker->borders, side = 1; side >= 0; side--, border++) {
|
|
PVG_FT_Vector point;
|
|
|
|
point.x = to->x + delta.x;
|
|
point.y = to->y + delta.y;
|
|
|
|
/* the ends of lineto borders are movable */
|
|
error = ft_stroke_border_lineto(border, &point, TRUE);
|
|
if (error) goto Exit;
|
|
|
|
delta.x = -delta.x;
|
|
delta.y = -delta.y;
|
|
}
|
|
|
|
stroker->angle_in = angle;
|
|
stroker->center = *to;
|
|
stroker->line_length = line_length;
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
PVG_FT_Error PVG_FT_Stroker_ConicTo(PVG_FT_Stroker stroker, PVG_FT_Vector* control,
|
|
PVG_FT_Vector* to)
|
|
{
|
|
PVG_FT_Error error = 0;
|
|
PVG_FT_Vector bez_stack[34];
|
|
PVG_FT_Vector* arc;
|
|
PVG_FT_Vector* limit = bez_stack + 30;
|
|
PVG_FT_Bool first_arc = TRUE;
|
|
|
|
/* if all control points are coincident, this is a no-op; */
|
|
/* avoid creating a spurious corner */
|
|
if (PVG_FT_IS_SMALL(stroker->center.x - control->x) &&
|
|
PVG_FT_IS_SMALL(stroker->center.y - control->y) &&
|
|
PVG_FT_IS_SMALL(control->x - to->x) &&
|
|
PVG_FT_IS_SMALL(control->y - to->y)) {
|
|
stroker->center = *to;
|
|
goto Exit;
|
|
}
|
|
|
|
arc = bez_stack;
|
|
arc[0] = *to;
|
|
arc[1] = *control;
|
|
arc[2] = stroker->center;
|
|
|
|
while (arc >= bez_stack) {
|
|
PVG_FT_Angle angle_in, angle_out;
|
|
|
|
/* initialize with current direction */
|
|
angle_in = angle_out = stroker->angle_in;
|
|
|
|
if (arc < limit &&
|
|
!ft_conic_is_small_enough(arc, &angle_in, &angle_out)) {
|
|
if (stroker->first_point) stroker->angle_in = angle_in;
|
|
|
|
ft_conic_split(arc);
|
|
arc += 2;
|
|
continue;
|
|
}
|
|
|
|
if (first_arc) {
|
|
first_arc = FALSE;
|
|
|
|
/* process corner if necessary */
|
|
if (stroker->first_point)
|
|
error = ft_stroker_subpath_start(stroker, angle_in, 0);
|
|
else {
|
|
stroker->angle_out = angle_in;
|
|
error = ft_stroker_process_corner(stroker, 0);
|
|
}
|
|
} else if (ft_pos_abs(PVG_FT_Angle_Diff(stroker->angle_in, angle_in)) >
|
|
PVG_FT_SMALL_CONIC_THRESHOLD / 4) {
|
|
/* if the deviation from one arc to the next is too great, */
|
|
/* add a round corner */
|
|
stroker->center = arc[2];
|
|
stroker->angle_out = angle_in;
|
|
stroker->line_join = PVG_FT_STROKER_LINEJOIN_ROUND;
|
|
|
|
error = ft_stroker_process_corner(stroker, 0);
|
|
|
|
/* reinstate line join style */
|
|
stroker->line_join = stroker->line_join_saved;
|
|
}
|
|
|
|
if (error) goto Exit;
|
|
|
|
/* the arc's angle is small enough; we can add it directly to each */
|
|
/* border */
|
|
{
|
|
PVG_FT_Vector ctrl, end;
|
|
PVG_FT_Angle theta, phi, rotate, alpha0 = 0;
|
|
PVG_FT_Fixed length;
|
|
PVG_FT_StrokeBorder border;
|
|
PVG_FT_Int side;
|
|
|
|
theta = PVG_FT_Angle_Diff(angle_in, angle_out) / 2;
|
|
phi = angle_in + theta;
|
|
length = PVG_FT_DivFix(stroker->radius, PVG_FT_Cos(theta));
|
|
|
|
/* compute direction of original arc */
|
|
if (stroker->handle_wide_strokes)
|
|
alpha0 = PVG_FT_Atan2(arc[0].x - arc[2].x, arc[0].y - arc[2].y);
|
|
|
|
for (border = stroker->borders, side = 0; side <= 1;
|
|
side++, border++) {
|
|
rotate = PVG_FT_SIDE_TO_ROTATE(side);
|
|
|
|
/* compute control point */
|
|
PVG_FT_Vector_From_Polar(&ctrl, length, phi + rotate);
|
|
ctrl.x += arc[1].x;
|
|
ctrl.y += arc[1].y;
|
|
|
|
/* compute end point */
|
|
PVG_FT_Vector_From_Polar(&end, stroker->radius,
|
|
angle_out + rotate);
|
|
end.x += arc[0].x;
|
|
end.y += arc[0].y;
|
|
|
|
if (stroker->handle_wide_strokes) {
|
|
PVG_FT_Vector start;
|
|
PVG_FT_Angle alpha1;
|
|
|
|
/* determine whether the border radius is greater than the
|
|
*/
|
|
/* radius of curvature of the original arc */
|
|
start = border->points[border->num_points - 1];
|
|
|
|
alpha1 = PVG_FT_Atan2(end.x - start.x, end.y - start.y);
|
|
|
|
/* is the direction of the border arc opposite to */
|
|
/* that of the original arc? */
|
|
if (ft_pos_abs(PVG_FT_Angle_Diff(alpha0, alpha1)) >
|
|
PVG_FT_ANGLE_PI / 2) {
|
|
PVG_FT_Angle beta, gamma;
|
|
PVG_FT_Vector bvec, delta;
|
|
PVG_FT_Fixed blen, sinA, sinB, alen;
|
|
|
|
/* use the sine rule to find the intersection point */
|
|
beta =
|
|
PVG_FT_Atan2(arc[2].x - start.x, arc[2].y - start.y);
|
|
gamma = PVG_FT_Atan2(arc[0].x - end.x, arc[0].y - end.y);
|
|
|
|
bvec.x = end.x - start.x;
|
|
bvec.y = end.y - start.y;
|
|
|
|
blen = PVG_FT_Vector_Length(&bvec);
|
|
|
|
sinA = ft_pos_abs(PVG_FT_Sin(alpha1 - gamma));
|
|
sinB = ft_pos_abs(PVG_FT_Sin(beta - gamma));
|
|
|
|
alen = PVG_FT_MulDiv(blen, sinA, sinB);
|
|
|
|
PVG_FT_Vector_From_Polar(&delta, alen, beta);
|
|
delta.x += start.x;
|
|
delta.y += start.y;
|
|
|
|
/* circumnavigate the negative sector backwards */
|
|
border->movable = FALSE;
|
|
error = ft_stroke_border_lineto(border, &delta, FALSE);
|
|
if (error) goto Exit;
|
|
error = ft_stroke_border_lineto(border, &end, FALSE);
|
|
if (error) goto Exit;
|
|
error = ft_stroke_border_conicto(border, &ctrl, &start);
|
|
if (error) goto Exit;
|
|
/* and then move to the endpoint */
|
|
error = ft_stroke_border_lineto(border, &end, FALSE);
|
|
if (error) goto Exit;
|
|
|
|
continue;
|
|
}
|
|
|
|
/* else fall through */
|
|
}
|
|
|
|
/* simply add an arc */
|
|
error = ft_stroke_border_conicto(border, &ctrl, &end);
|
|
if (error) goto Exit;
|
|
}
|
|
}
|
|
|
|
arc -= 2;
|
|
|
|
stroker->angle_in = angle_out;
|
|
}
|
|
|
|
stroker->center = *to;
|
|
stroker->line_length = 0;
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
PVG_FT_Error PVG_FT_Stroker_CubicTo(PVG_FT_Stroker stroker, PVG_FT_Vector* control1,
|
|
PVG_FT_Vector* control2, PVG_FT_Vector* to)
|
|
{
|
|
PVG_FT_Error error = 0;
|
|
PVG_FT_Vector bez_stack[37];
|
|
PVG_FT_Vector* arc;
|
|
PVG_FT_Vector* limit = bez_stack + 32;
|
|
PVG_FT_Bool first_arc = TRUE;
|
|
|
|
/* if all control points are coincident, this is a no-op; */
|
|
/* avoid creating a spurious corner */
|
|
if (PVG_FT_IS_SMALL(stroker->center.x - control1->x) &&
|
|
PVG_FT_IS_SMALL(stroker->center.y - control1->y) &&
|
|
PVG_FT_IS_SMALL(control1->x - control2->x) &&
|
|
PVG_FT_IS_SMALL(control1->y - control2->y) &&
|
|
PVG_FT_IS_SMALL(control2->x - to->x) &&
|
|
PVG_FT_IS_SMALL(control2->y - to->y)) {
|
|
stroker->center = *to;
|
|
goto Exit;
|
|
}
|
|
|
|
arc = bez_stack;
|
|
arc[0] = *to;
|
|
arc[1] = *control2;
|
|
arc[2] = *control1;
|
|
arc[3] = stroker->center;
|
|
|
|
while (arc >= bez_stack) {
|
|
PVG_FT_Angle angle_in, angle_mid, angle_out;
|
|
|
|
/* initialize with current direction */
|
|
angle_in = angle_out = angle_mid = stroker->angle_in;
|
|
|
|
if (arc < limit &&
|
|
!ft_cubic_is_small_enough(arc, &angle_in, &angle_mid, &angle_out)) {
|
|
if (stroker->first_point) stroker->angle_in = angle_in;
|
|
|
|
ft_cubic_split(arc);
|
|
arc += 3;
|
|
continue;
|
|
}
|
|
|
|
if (first_arc) {
|
|
first_arc = FALSE;
|
|
|
|
/* process corner if necessary */
|
|
if (stroker->first_point)
|
|
error = ft_stroker_subpath_start(stroker, angle_in, 0);
|
|
else {
|
|
stroker->angle_out = angle_in;
|
|
error = ft_stroker_process_corner(stroker, 0);
|
|
}
|
|
} else if (ft_pos_abs(PVG_FT_Angle_Diff(stroker->angle_in, angle_in)) >
|
|
PVG_FT_SMALL_CUBIC_THRESHOLD / 4) {
|
|
/* if the deviation from one arc to the next is too great, */
|
|
/* add a round corner */
|
|
stroker->center = arc[3];
|
|
stroker->angle_out = angle_in;
|
|
stroker->line_join = PVG_FT_STROKER_LINEJOIN_ROUND;
|
|
|
|
error = ft_stroker_process_corner(stroker, 0);
|
|
|
|
/* reinstate line join style */
|
|
stroker->line_join = stroker->line_join_saved;
|
|
}
|
|
|
|
if (error) goto Exit;
|
|
|
|
/* the arc's angle is small enough; we can add it directly to each */
|
|
/* border */
|
|
{
|
|
PVG_FT_Vector ctrl1, ctrl2, end;
|
|
PVG_FT_Angle theta1, phi1, theta2, phi2, rotate, alpha0 = 0;
|
|
PVG_FT_Fixed length1, length2;
|
|
PVG_FT_StrokeBorder border;
|
|
PVG_FT_Int side;
|
|
|
|
theta1 = PVG_FT_Angle_Diff(angle_in, angle_mid) / 2;
|
|
theta2 = PVG_FT_Angle_Diff(angle_mid, angle_out) / 2;
|
|
phi1 = ft_angle_mean(angle_in, angle_mid);
|
|
phi2 = ft_angle_mean(angle_mid, angle_out);
|
|
length1 = PVG_FT_DivFix(stroker->radius, PVG_FT_Cos(theta1));
|
|
length2 = PVG_FT_DivFix(stroker->radius, PVG_FT_Cos(theta2));
|
|
|
|
/* compute direction of original arc */
|
|
if (stroker->handle_wide_strokes)
|
|
alpha0 = PVG_FT_Atan2(arc[0].x - arc[3].x, arc[0].y - arc[3].y);
|
|
|
|
for (border = stroker->borders, side = 0; side <= 1;
|
|
side++, border++) {
|
|
rotate = PVG_FT_SIDE_TO_ROTATE(side);
|
|
|
|
/* compute control points */
|
|
PVG_FT_Vector_From_Polar(&ctrl1, length1, phi1 + rotate);
|
|
ctrl1.x += arc[2].x;
|
|
ctrl1.y += arc[2].y;
|
|
|
|
PVG_FT_Vector_From_Polar(&ctrl2, length2, phi2 + rotate);
|
|
ctrl2.x += arc[1].x;
|
|
ctrl2.y += arc[1].y;
|
|
|
|
/* compute end point */
|
|
PVG_FT_Vector_From_Polar(&end, stroker->radius,
|
|
angle_out + rotate);
|
|
end.x += arc[0].x;
|
|
end.y += arc[0].y;
|
|
|
|
if (stroker->handle_wide_strokes) {
|
|
PVG_FT_Vector start;
|
|
PVG_FT_Angle alpha1;
|
|
|
|
/* determine whether the border radius is greater than the
|
|
*/
|
|
/* radius of curvature of the original arc */
|
|
start = border->points[border->num_points - 1];
|
|
|
|
alpha1 = PVG_FT_Atan2(end.x - start.x, end.y - start.y);
|
|
|
|
/* is the direction of the border arc opposite to */
|
|
/* that of the original arc? */
|
|
if (ft_pos_abs(PVG_FT_Angle_Diff(alpha0, alpha1)) >
|
|
PVG_FT_ANGLE_PI / 2) {
|
|
PVG_FT_Angle beta, gamma;
|
|
PVG_FT_Vector bvec, delta;
|
|
PVG_FT_Fixed blen, sinA, sinB, alen;
|
|
|
|
/* use the sine rule to find the intersection point */
|
|
beta =
|
|
PVG_FT_Atan2(arc[3].x - start.x, arc[3].y - start.y);
|
|
gamma = PVG_FT_Atan2(arc[0].x - end.x, arc[0].y - end.y);
|
|
|
|
bvec.x = end.x - start.x;
|
|
bvec.y = end.y - start.y;
|
|
|
|
blen = PVG_FT_Vector_Length(&bvec);
|
|
|
|
sinA = ft_pos_abs(PVG_FT_Sin(alpha1 - gamma));
|
|
sinB = ft_pos_abs(PVG_FT_Sin(beta - gamma));
|
|
|
|
alen = PVG_FT_MulDiv(blen, sinA, sinB);
|
|
|
|
PVG_FT_Vector_From_Polar(&delta, alen, beta);
|
|
delta.x += start.x;
|
|
delta.y += start.y;
|
|
|
|
/* circumnavigate the negative sector backwards */
|
|
border->movable = FALSE;
|
|
error = ft_stroke_border_lineto(border, &delta, FALSE);
|
|
if (error) goto Exit;
|
|
error = ft_stroke_border_lineto(border, &end, FALSE);
|
|
if (error) goto Exit;
|
|
error = ft_stroke_border_cubicto(border, &ctrl2, &ctrl1,
|
|
&start);
|
|
if (error) goto Exit;
|
|
/* and then move to the endpoint */
|
|
error = ft_stroke_border_lineto(border, &end, FALSE);
|
|
if (error) goto Exit;
|
|
|
|
continue;
|
|
}
|
|
|
|
/* else fall through */
|
|
}
|
|
|
|
/* simply add an arc */
|
|
error = ft_stroke_border_cubicto(border, &ctrl1, &ctrl2, &end);
|
|
if (error) goto Exit;
|
|
}
|
|
}
|
|
|
|
arc -= 3;
|
|
|
|
stroker->angle_in = angle_out;
|
|
}
|
|
|
|
stroker->center = *to;
|
|
stroker->line_length = 0;
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
PVG_FT_Error PVG_FT_Stroker_BeginSubPath(PVG_FT_Stroker stroker, PVG_FT_Vector* to,
|
|
PVG_FT_Bool open)
|
|
{
|
|
/* We cannot process the first point, because there is not enough */
|
|
/* information regarding its corner/cap. The latter will be processed */
|
|
/* in the `PVG_FT_Stroker_EndSubPath' routine. */
|
|
/* */
|
|
stroker->first_point = TRUE;
|
|
stroker->center = *to;
|
|
stroker->subpath_open = open;
|
|
|
|
/* Determine if we need to check whether the border radius is greater */
|
|
/* than the radius of curvature of a curve, to handle this case */
|
|
/* specially. This is only required if bevel joins or butt caps may */
|
|
/* be created, because round & miter joins and round & square caps */
|
|
/* cover the negative sector created with wide strokes. */
|
|
stroker->handle_wide_strokes =
|
|
PVG_FT_BOOL(stroker->line_join != PVG_FT_STROKER_LINEJOIN_ROUND ||
|
|
(stroker->subpath_open &&
|
|
stroker->line_cap == PVG_FT_STROKER_LINECAP_BUTT));
|
|
|
|
/* record the subpath start point for each border */
|
|
stroker->subpath_start = *to;
|
|
|
|
stroker->angle_in = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static PVG_FT_Error ft_stroker_add_reverse_left(PVG_FT_Stroker stroker,
|
|
PVG_FT_Bool open)
|
|
{
|
|
PVG_FT_StrokeBorder right = stroker->borders + 0;
|
|
PVG_FT_StrokeBorder left = stroker->borders + 1;
|
|
PVG_FT_Int new_points;
|
|
PVG_FT_Error error = 0;
|
|
|
|
assert(left->start >= 0);
|
|
|
|
new_points = left->num_points - left->start;
|
|
if (new_points > 0) {
|
|
error = ft_stroke_border_grow(right, (PVG_FT_UInt)new_points);
|
|
if (error) goto Exit;
|
|
|
|
{
|
|
PVG_FT_Vector* dst_point = right->points + right->num_points;
|
|
PVG_FT_Byte* dst_tag = right->tags + right->num_points;
|
|
PVG_FT_Vector* src_point = left->points + left->num_points - 1;
|
|
PVG_FT_Byte* src_tag = left->tags + left->num_points - 1;
|
|
|
|
while (src_point >= left->points + left->start) {
|
|
*dst_point = *src_point;
|
|
*dst_tag = *src_tag;
|
|
|
|
if (open)
|
|
dst_tag[0] &= ~PVG_FT_STROKE_TAG_BEGIN_END;
|
|
else {
|
|
PVG_FT_Byte ttag =
|
|
(PVG_FT_Byte)(dst_tag[0] & PVG_FT_STROKE_TAG_BEGIN_END);
|
|
|
|
/* switch begin/end tags if necessary */
|
|
if (ttag == PVG_FT_STROKE_TAG_BEGIN ||
|
|
ttag == PVG_FT_STROKE_TAG_END)
|
|
dst_tag[0] ^= PVG_FT_STROKE_TAG_BEGIN_END;
|
|
}
|
|
|
|
src_point--;
|
|
src_tag--;
|
|
dst_point++;
|
|
dst_tag++;
|
|
}
|
|
}
|
|
|
|
left->num_points = left->start;
|
|
right->num_points += new_points;
|
|
|
|
right->movable = FALSE;
|
|
left->movable = FALSE;
|
|
}
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
/* there's a lot of magic in this function! */
|
|
PVG_FT_Error PVG_FT_Stroker_EndSubPath(PVG_FT_Stroker stroker)
|
|
{
|
|
PVG_FT_Error error = 0;
|
|
|
|
if (stroker->subpath_open) {
|
|
PVG_FT_StrokeBorder right = stroker->borders;
|
|
|
|
/* All right, this is an opened path, we need to add a cap between */
|
|
/* right & left, add the reverse of left, then add a final cap */
|
|
/* between left & right. */
|
|
error = ft_stroker_cap(stroker, stroker->angle_in, 0);
|
|
if (error) goto Exit;
|
|
|
|
/* add reversed points from `left' to `right' */
|
|
error = ft_stroker_add_reverse_left(stroker, TRUE);
|
|
if (error) goto Exit;
|
|
|
|
/* now add the final cap */
|
|
stroker->center = stroker->subpath_start;
|
|
error =
|
|
ft_stroker_cap(stroker, stroker->subpath_angle + PVG_FT_ANGLE_PI, 0);
|
|
if (error) goto Exit;
|
|
|
|
/* Now end the right subpath accordingly. The left one is */
|
|
/* rewind and doesn't need further processing. */
|
|
ft_stroke_border_close(right, FALSE);
|
|
} else {
|
|
PVG_FT_Angle turn;
|
|
PVG_FT_Int inside_side;
|
|
|
|
/* close the path if needed */
|
|
if (stroker->center.x != stroker->subpath_start.x ||
|
|
stroker->center.y != stroker->subpath_start.y) {
|
|
error = PVG_FT_Stroker_LineTo(stroker, &stroker->subpath_start);
|
|
if (error) goto Exit;
|
|
}
|
|
|
|
/* process the corner */
|
|
stroker->angle_out = stroker->subpath_angle;
|
|
turn = PVG_FT_Angle_Diff(stroker->angle_in, stroker->angle_out);
|
|
|
|
/* no specific corner processing is required if the turn is 0 */
|
|
if (turn != 0) {
|
|
/* when we turn to the right, the inside side is 0 */
|
|
inside_side = 0;
|
|
|
|
/* otherwise, the inside side is 1 */
|
|
if (turn < 0) inside_side = 1;
|
|
|
|
error = ft_stroker_inside(stroker, inside_side,
|
|
stroker->subpath_line_length);
|
|
if (error) goto Exit;
|
|
|
|
/* process the outside side */
|
|
error = ft_stroker_outside(stroker, 1 - inside_side,
|
|
stroker->subpath_line_length);
|
|
if (error) goto Exit;
|
|
}
|
|
|
|
/* then end our two subpaths */
|
|
ft_stroke_border_close(stroker->borders + 0, FALSE);
|
|
ft_stroke_border_close(stroker->borders + 1, TRUE);
|
|
}
|
|
|
|
Exit:
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
PVG_FT_Error PVG_FT_Stroker_GetBorderCounts(PVG_FT_Stroker stroker,
|
|
PVG_FT_StrokerBorder border,
|
|
PVG_FT_UInt* anum_points,
|
|
PVG_FT_UInt* anum_contours)
|
|
{
|
|
PVG_FT_UInt num_points = 0, num_contours = 0;
|
|
PVG_FT_Error error;
|
|
|
|
if (!stroker || border > 1) {
|
|
error = -1; // PVG_FT_THROW( Invalid_Argument );
|
|
goto Exit;
|
|
}
|
|
|
|
error = ft_stroke_border_get_counts(stroker->borders + border, &num_points,
|
|
&num_contours);
|
|
Exit:
|
|
if (anum_points) *anum_points = num_points;
|
|
|
|
if (anum_contours) *anum_contours = num_contours;
|
|
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
PVG_FT_Error PVG_FT_Stroker_GetCounts(PVG_FT_Stroker stroker,
|
|
PVG_FT_UInt* anum_points,
|
|
PVG_FT_UInt* anum_contours)
|
|
{
|
|
PVG_FT_UInt count1, count2, num_points = 0;
|
|
PVG_FT_UInt count3, count4, num_contours = 0;
|
|
PVG_FT_Error error;
|
|
|
|
error = ft_stroke_border_get_counts(stroker->borders + 0, &count1, &count2);
|
|
if (error) goto Exit;
|
|
|
|
error = ft_stroke_border_get_counts(stroker->borders + 1, &count3, &count4);
|
|
if (error) goto Exit;
|
|
|
|
num_points = count1 + count3;
|
|
num_contours = count2 + count4;
|
|
|
|
Exit:
|
|
*anum_points = num_points;
|
|
*anum_contours = num_contours;
|
|
return error;
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
void PVG_FT_Stroker_ExportBorder(PVG_FT_Stroker stroker,
|
|
PVG_FT_StrokerBorder border,
|
|
PVG_FT_Outline* outline)
|
|
{
|
|
if (border == PVG_FT_STROKER_BORDER_LEFT ||
|
|
border == PVG_FT_STROKER_BORDER_RIGHT) {
|
|
PVG_FT_StrokeBorder sborder = &stroker->borders[border];
|
|
|
|
if (sborder->valid) ft_stroke_border_export(sborder, outline);
|
|
}
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
void PVG_FT_Stroker_Export(PVG_FT_Stroker stroker, PVG_FT_Outline* outline)
|
|
{
|
|
PVG_FT_Stroker_ExportBorder(stroker, PVG_FT_STROKER_BORDER_LEFT, outline);
|
|
PVG_FT_Stroker_ExportBorder(stroker, PVG_FT_STROKER_BORDER_RIGHT, outline);
|
|
}
|
|
|
|
/* documentation is in ftstroke.h */
|
|
|
|
/*
|
|
* The following is very similar to PVG_FT_Outline_Decompose, except
|
|
* that we do support opened paths, and do not scale the outline.
|
|
*/
|
|
PVG_FT_Error PVG_FT_Stroker_ParseOutline(PVG_FT_Stroker stroker,
|
|
const PVG_FT_Outline* outline)
|
|
{
|
|
PVG_FT_Vector v_last;
|
|
PVG_FT_Vector v_control;
|
|
PVG_FT_Vector v_start;
|
|
|
|
PVG_FT_Vector* point;
|
|
PVG_FT_Vector* limit;
|
|
char* tags;
|
|
|
|
PVG_FT_Error error;
|
|
|
|
PVG_FT_Int n; /* index of contour in outline */
|
|
PVG_FT_UInt first; /* index of first point in contour */
|
|
PVG_FT_Int tag; /* current point's state */
|
|
|
|
if (!outline || !stroker) return -1; // PVG_FT_THROW( Invalid_Argument );
|
|
|
|
PVG_FT_Stroker_Rewind(stroker);
|
|
|
|
first = 0;
|
|
|
|
for (n = 0; n < outline->n_contours; n++) {
|
|
PVG_FT_UInt last; /* index of last point in contour */
|
|
|
|
last = outline->contours[n];
|
|
limit = outline->points + last;
|
|
|
|
/* skip empty points; we don't stroke these */
|
|
if (last <= first) {
|
|
first = last + 1;
|
|
continue;
|
|
}
|
|
|
|
v_start = outline->points[first];
|
|
v_last = outline->points[last];
|
|
|
|
v_control = v_start;
|
|
|
|
point = outline->points + first;
|
|
tags = outline->tags + first;
|
|
tag = PVG_FT_CURVE_TAG(tags[0]);
|
|
|
|
/* A contour cannot start with a cubic control point! */
|
|
if (tag == PVG_FT_CURVE_TAG_CUBIC) goto Invalid_Outline;
|
|
|
|
/* check first point to determine origin */
|
|
if (tag == PVG_FT_CURVE_TAG_CONIC) {
|
|
/* First point is conic control. Yes, this happens. */
|
|
if (PVG_FT_CURVE_TAG(outline->tags[last]) == PVG_FT_CURVE_TAG_ON) {
|
|
/* start at last point if it is on the curve */
|
|
v_start = v_last;
|
|
limit--;
|
|
} else {
|
|
/* if both first and last points are conic, */
|
|
/* start at their middle */
|
|
v_start.x = (v_start.x + v_last.x) / 2;
|
|
v_start.y = (v_start.y + v_last.y) / 2;
|
|
}
|
|
point--;
|
|
tags--;
|
|
}
|
|
|
|
error = PVG_FT_Stroker_BeginSubPath(stroker, &v_start, outline->contours_flag[n]);
|
|
if (error) goto Exit;
|
|
|
|
while (point < limit) {
|
|
point++;
|
|
tags++;
|
|
|
|
tag = PVG_FT_CURVE_TAG(tags[0]);
|
|
switch (tag) {
|
|
case PVG_FT_CURVE_TAG_ON: /* emit a single line_to */
|
|
{
|
|
PVG_FT_Vector vec;
|
|
|
|
vec.x = point->x;
|
|
vec.y = point->y;
|
|
|
|
error = PVG_FT_Stroker_LineTo(stroker, &vec);
|
|
if (error) goto Exit;
|
|
continue;
|
|
}
|
|
|
|
case PVG_FT_CURVE_TAG_CONIC: /* consume conic arcs */
|
|
v_control.x = point->x;
|
|
v_control.y = point->y;
|
|
|
|
Do_Conic:
|
|
if (point < limit) {
|
|
PVG_FT_Vector vec;
|
|
PVG_FT_Vector v_middle;
|
|
|
|
point++;
|
|
tags++;
|
|
tag = PVG_FT_CURVE_TAG(tags[0]);
|
|
|
|
vec = point[0];
|
|
|
|
if (tag == PVG_FT_CURVE_TAG_ON) {
|
|
error =
|
|
PVG_FT_Stroker_ConicTo(stroker, &v_control, &vec);
|
|
if (error) goto Exit;
|
|
continue;
|
|
}
|
|
|
|
if (tag != PVG_FT_CURVE_TAG_CONIC) goto Invalid_Outline;
|
|
|
|
v_middle.x = (v_control.x + vec.x) / 2;
|
|
v_middle.y = (v_control.y + vec.y) / 2;
|
|
|
|
error =
|
|
PVG_FT_Stroker_ConicTo(stroker, &v_control, &v_middle);
|
|
if (error) goto Exit;
|
|
|
|
v_control = vec;
|
|
goto Do_Conic;
|
|
}
|
|
|
|
error = PVG_FT_Stroker_ConicTo(stroker, &v_control, &v_start);
|
|
goto Close;
|
|
|
|
default: /* PVG_FT_CURVE_TAG_CUBIC */
|
|
{
|
|
PVG_FT_Vector vec1, vec2;
|
|
|
|
if (point + 1 > limit ||
|
|
PVG_FT_CURVE_TAG(tags[1]) != PVG_FT_CURVE_TAG_CUBIC)
|
|
goto Invalid_Outline;
|
|
|
|
point += 2;
|
|
tags += 2;
|
|
|
|
vec1 = point[-2];
|
|
vec2 = point[-1];
|
|
|
|
if (point <= limit) {
|
|
PVG_FT_Vector vec;
|
|
|
|
vec = point[0];
|
|
|
|
error = PVG_FT_Stroker_CubicTo(stroker, &vec1, &vec2, &vec);
|
|
if (error) goto Exit;
|
|
continue;
|
|
}
|
|
|
|
error = PVG_FT_Stroker_CubicTo(stroker, &vec1, &vec2, &v_start);
|
|
goto Close;
|
|
}
|
|
}
|
|
}
|
|
|
|
Close:
|
|
if (error) goto Exit;
|
|
|
|
if (stroker->first_point) {
|
|
stroker->subpath_open = TRUE;
|
|
error = ft_stroker_subpath_start(stroker, 0, 0);
|
|
if (error) goto Exit;
|
|
}
|
|
|
|
error = PVG_FT_Stroker_EndSubPath(stroker);
|
|
if (error) goto Exit;
|
|
|
|
first = last + 1;
|
|
}
|
|
|
|
return 0;
|
|
|
|
Exit:
|
|
return error;
|
|
|
|
Invalid_Outline:
|
|
return -2; // PVG_FT_THROW( Invalid_Outline );
|
|
}
|
|
|
|
/* END */
|