From fb585b0065c8e458b460a3f8d67c71048b9ca5d8 Mon Sep 17 00:00:00 2001
From: Milan Nikolic <gen2brain@gmail.com>
Date: Fri, 27 Oct 2017 13:59:05 +0200
Subject: [PATCH] Add ToImage/FromImage helpers for Go image.Image interface

---
 examples/textures/image_image/main.go | 40 +++++++++++++++------------
 raylib/textures.go                    | 34 ++++++++++++++++++++++-
 2 files changed, 55 insertions(+), 19 deletions(-)

diff --git a/examples/textures/image_image/main.go b/examples/textures/image_image/main.go
index 272d07b..82d3e5a 100644
--- a/examples/textures/image_image/main.go
+++ b/examples/textures/image_image/main.go
@@ -24,33 +24,37 @@ func main() {
 		raylib.TraceLog(raylib.LogError, err.Error())
 	}
 
-	// Get image size
-	size := img.Bounds().Size()
-
-	// Dynamic memory allocation to store pixels data (Color type)
-	pixels := make([]raylib.Color, size.X*size.Y)
-
-	for y := 0; y < size.Y; y++ {
-		for x := 0; x < size.X; x++ {
-			color := img.At(x, y)
-			r, g, b, a := color.RGBA()
-			pixels[x+y*size.Y] = raylib.NewColor(uint8(r), uint8(g), uint8(b), uint8(a))
-		}
-	}
-
-	// Load pixels data into an image structure and create texture
-	imEx := raylib.LoadImageEx(pixels, int32(size.X), int32(size.Y))
-	texture := raylib.LoadTextureFromImage(imEx)
+	// Create raylib.Image from Go image.Image and create texture
+	im := raylib.NewImageFromImage(img)
+	texture := raylib.LoadTextureFromImage(im)
 
 	// Unload CPU (RAM) image data
-	raylib.UnloadImage(imEx)
+	raylib.UnloadImage(im)
 
 	raylib.SetTargetFPS(60)
 
 	for !raylib.WindowShouldClose() {
+		if raylib.IsKeyPressed(raylib.KeyS) {
+			rimg := raylib.GetTextureData(texture)
+
+			f, err := os.Create("image_saved.png")
+			if err != nil {
+				raylib.TraceLog(raylib.LogError, err.Error())
+			}
+
+			err = png.Encode(f, rimg.ToImage())
+			if err != nil {
+				raylib.TraceLog(raylib.LogError, err.Error())
+			}
+
+			f.Close()
+		}
+
 		raylib.BeginDrawing()
 
 		raylib.ClearBackground(raylib.RayWhite)
+
+		raylib.DrawText("PRESS S TO SAVE IMAGE FROM TEXTURE", 20, 20, 12, raylib.LightGray)
 		raylib.DrawTexture(texture, screenWidth/2-texture.Width/2, screenHeight/2-texture.Height/2, raylib.White)
 		raylib.DrawText("this IS a texture loaded from an image.Image!", 285, 370, 10, raylib.Gray)
 
diff --git a/raylib/textures.go b/raylib/textures.go
index 41d5714..2fe8ac5 100644
--- a/raylib/textures.go
+++ b/raylib/textures.go
@@ -5,7 +5,11 @@ package raylib
 #include <stdlib.h>
 */
 import "C"
-import "unsafe"
+
+import (
+	"image"
+	"unsafe"
+)
 
 // TextureFormat - Texture format
 type TextureFormat int32
@@ -101,6 +105,18 @@ func (i *Image) cptr() *C.Image {
 	return (*C.Image)(unsafe.Pointer(i))
 }
 
+// ToImage converts a Image to Go image.Image
+func (i *Image) ToImage() image.Image {
+	img := image.NewRGBA(image.Rect(0, 0, int(i.Width), int(i.Height)))
+
+	// Get pixel data from image (RGBA 32bit)
+	pixels := GetImageData(i)
+
+	img.Pix = (*[1 << 30]uint8)(pixels)[:]
+
+	return img
+}
+
 // NewImage - Returns new Image
 func NewImage(data unsafe.Pointer, width, height, mipmaps int32, format TextureFormat) *Image {
 	return &Image{data, width, height, mipmaps, format}
@@ -111,6 +127,22 @@ func NewImageFromPointer(ptr unsafe.Pointer) *Image {
 	return (*Image)(ptr)
 }
 
+// NewImageFromImage - Returns new Image from Go image.Image
+func NewImageFromImage(img image.Image) *Image {
+	size := img.Bounds().Size()
+	pixels := make([]Color, size.X*size.Y)
+
+	for y := 0; y < size.Y; y++ {
+		for x := 0; x < size.X; x++ {
+			color := img.At(x, y)
+			r, g, b, a := color.RGBA()
+			pixels[x+y*size.Y] = NewColor(uint8(r), uint8(g), uint8(b), uint8(a))
+		}
+	}
+
+	return LoadImageEx(pixels, int32(size.X), int32(size.Y))
+}
+
 // Texture2D type, bpp always RGBA (32bit)
 // NOTE: Data stored in GPU memory
 type Texture2D struct {