ES-DE/es-core/src/components/NinePatchComponent.h

#pragma once

#include "GuiComponent.h"
#include "resources/TextureResource.h"

// Display an image in a way so that edges don't get too distorted no matter the final size. Useful for UI elements like backgrounds, buttons, etc.
// This is accomplished by splitting an image into 9 pieces:
//  ___________
// |_1_|_2_|_3_|
// |_4_|_5_|_6_|
// |_7_|_8_|_9_|

// Corners (1, 3, 7, 9) will not be stretched at all.
// Borders (2, 4, 6, 8) will be stretched along one axis (2 and 8 horizontally, 4 and 6 vertically).
// The center (5) will be stretched.

class NinePatchComponent : public GuiComponent
{
public:
	NinePatchComponent(Window* window, const std::string& path = "", unsigned int edgeColor = 0xFFFFFFFF, unsigned int centerColor = 0xFFFFFFFF);

	void render(const Eigen::Affine3f& parentTrans) override;

	void onSizeChanged() override;

	void fitTo(Eigen::Vector2f size, Eigen::Vector3f position = Eigen::Vector3f::Zero(), Eigen::Vector2f padding = Eigen::Vector2f::Zero());

	void setImagePath(const std::string& path);
	void setEdgeColor(unsigned int edgeColor); // Apply a color shift to the "edge" parts of the ninepatch.
	void setCenterColor(unsigned int centerColor); // Apply a color shift to the "center" part of the ninepatch.

	virtual void applyTheme(const std::shared_ptr<ThemeData>& theme, const std::string& view, const std::string& element, unsigned int properties) override;

private:
	Eigen::Vector2f getCornerSize() const;

	void buildVertices();
	void updateColors();

	struct Vertex
	{
		Eigen::Vector2f pos;
		Eigen::Vector2f tex;
	};

	Vertex* mVertices;
	GLubyte* mColors;

	std::string mPath;
	unsigned int mEdgeColor;
	unsigned int mCenterColor;
	std::shared_ptr<TextureResource> mTexture;
};