Added utility function to write BMP files

Src/Util/BMPFile.cpp

@@ -0,0 +1,113 @@
+#include "Util/BMPFile.h"
+#include "OSD/Logger.h"
+#include <memory>
+#include <cstdio>
+
+namespace Util
+{
+  #pragma pack(push, 1)
+
+  struct BMPHeader
+  {
+    uint8_t id[2];
+    uint32_t file_size;
+    uint16_t reserved1;
+    uint16_t reserved2;
+    uint32_t bitmap_offset;
+    BMPHeader(uint32_t _file_size, uint32_t _bitmap_offset)
+      : id{ 'B', 'M' },
+        file_size(_file_size),
+        reserved1(0),
+        reserved2(0),
+        bitmap_offset(_bitmap_offset)
+    {}  
+  };
+  
+  struct BMPInfoHeader
+  {
+    uint32_t size;
+    int32_t width;
+    int32_t height;
+    uint16_t num_planes;
+    uint16_t bits_per_pixel;
+    uint32_t compression_method;
+    uint32_t bitmap_size;
+    int32_t horizontal_resolution;
+    int32_t vertical_resolution;
+    uint32_t num_palette_colors;
+    uint32_t num_important_colors;
+    BMPInfoHeader(int32_t _width, int32_t _height)
+      : size(sizeof(BMPInfoHeader)),
+        width(_width),
+        height(_height),
+        num_planes(1),
+        bits_per_pixel(24),
+        compression_method(0),
+        bitmap_size(_width*_height*3),
+        horizontal_resolution(2835),  // 72 dpi
+        vertical_resolution(2835),
+        num_palette_colors(0),
+        num_important_colors(0)
+    {}
+  };
+  
+  struct FileHeader
+  {
+    BMPHeader bmp_header;
+    BMPInfoHeader bmp_info_header;
+    FileHeader(int32_t width, int32_t height)
+      : bmp_header(sizeof(FileHeader) + width*height*3, sizeof(FileHeader)),
+        bmp_info_header(width, height)
+    {}
+  };
+
+  #pragma pack(pop)
+  
+  bool WriteRGBA8SurfaceToBMP(const std::string &file_name, const uint8_t *pixels, int32_t width, int32_t height, bool flip_vertical)
+  {
+    size_t file_size = sizeof(FileHeader) + width*height*3;
+    std::shared_ptr<uint8_t> file(new uint8_t[file_size], std::default_delete<uint8_t[]>());
+    FileHeader *header = new (file.get()) FileHeader(width, height);
+    uint8_t *bmp = file.get() + sizeof(*header);
+    if (!flip_vertical)
+    {
+      for (int32_t y = height - 1; y >= 0; y--)
+      {
+        const uint8_t *src = &pixels[y*width*4];
+        for (int32_t x = 0; x < width; x++)
+        {
+          *bmp++ = src[2];  // b
+          *bmp++ = src[1];  // g
+          *bmp++ = src[0];  // r
+          src += 4;
+        }
+      }
+    }
+    else
+    {
+      for (int32_t y = 0; y < height; y++)
+      {
+        const uint8_t *src = &pixels[y*width*4];
+        for (int32_t x = 0; x < width; x++)
+        {
+          *bmp++ = src[2];  // b
+          *bmp++ = src[1];  // g
+          *bmp++ = src[0];  // r
+          src += 4;
+        }
+      }
+    }
+    FILE *fp = fopen(file_name.c_str(), "wb");
+    if (fp)
+    {
+      fwrite(file.get(), sizeof(uint8_t), file_size, fp);
+      fclose(fp);
+    }
+    else
+    {
+      ErrorLog("Unable to open '%s' for writing.", file_name.c_str());
+      return true;
+    }
+    return false;
+  }
+} // Util

Src/Util/BMPFile.h

@@ -0,0 +1,12 @@
+#ifndef INCLUDED_BMPFILE_HPP
+#define INCLUDED_BMPFILE_HPP
+
+#include <string>
+#include <cstdint>
+
+namespace Util
+{
+  extern bool WriteRGBA8SurfaceToBMP(const std::string &file_name, const uint8_t *pixels, int32_t width, int32_t height, bool flip_vertical);
+} // Util
+
+#endif  // INCLUDED_BMPFILE_HPP