From 278d8575bdd09ba6536291e1b66dc9d32224fb2d Mon Sep 17 00:00:00 2001
From: Ray <raysan5@gmail.com>
Date: Thu, 11 Jan 2018 10:22:32 +0100
Subject: [PATCH] Added new function: ImageAlphaCrop()

---
 src/raylib.h   |  1 +
 src/textures.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/src/raylib.h b/src/raylib.h
index b482ab3b6..dc02370da 100644
--- a/src/raylib.h
+++ b/src/raylib.h
@@ -881,6 +881,7 @@ RLAPI void ImageToPOT(Image *image, Color fillColor);
 RLAPI void ImageFormat(Image *image, int newFormat);                                                     // Convert image data to desired format
 RLAPI void ImageAlphaMask(Image *image, Image alphaMask);                                                // Apply alpha mask to image
 RLAPI void ImageAlphaClear(Image *image, Color color, float threshold);                                  // Clear alpha channel to desired color
+RLAPI void ImageAlphaCrop(Image *image, float threshold);                                                // Crop image depending on alpha value
 RLAPI void ImageAlphaPremultiply(Image *image);                                                          // Premultiply alpha channel
 RLAPI void ImageCrop(Image *image, Rectangle crop);                                                      // Crop an image to a defined rectangle
 RLAPI void ImageResize(Image *image, int newWidth, int newHeight);                                       // Resize and image (bilinear filtering)
diff --git a/src/textures.c b/src/textures.c
index 44a9fef2e..665e54474 100644
--- a/src/textures.c
+++ b/src/textures.c
@@ -890,6 +890,51 @@ void ImageAlphaClear(Image *image, Color color, float threshold)
     ImageFormat(image, prevFormat);
 }
 
+// Crop image depending on alpha value
+void ImageAlphaCrop(Image *image, float threshold)
+{
+    Rectangle crop = { 0 };
+    
+    Color *pixels = GetImageData(*image);
+    
+    int minx = 0;
+    int miny = 0;
+
+    for (int i = 0; i < image->width*image->height; i++) 
+    {
+        if (pixels[i].a > (unsigned char)(threshold*255.0f))
+        {
+            minx = i%image->width;
+            miny = -(-((i/image->width) + 1) + 1);
+
+            if (crop.y == 0) crop.y = miny;
+
+            if (crop.x == 0) crop.x = minx;
+            else if (minx < crop.x) crop.x = minx;
+
+            if (crop.width == 0) crop.width = minx; 
+            else if (crop.width < minx) crop.width = minx;
+
+            if (crop.height == 0) crop.height = miny;
+            else if (crop.height < miny) crop.height = miny;
+        }
+    }
+    
+    crop.width -= (crop.x - 1);
+    crop.height -= (crop.y - 1);
+    
+    TraceLog(LOG_INFO, "Crop rectangle: (%i, %i, %i, %i)", crop.x, crop.y, crop.width, crop.height);
+    
+    free(pixels);
+    
+    // NOTE: Added this weird check to avoid additional 1px crop to
+    // image data that has already been cropped...
+    if ((crop.x != 1) && 
+        (crop.y != 1) && 
+        (crop.width != image->width - 1) &&
+        (crop.height != image->height - 1)) ImageCrop(image, crop);
+}
+
 // Premultiply alpha channel
 void ImageAlphaPremultiply(Image *image)
 {
@@ -912,6 +957,8 @@ void ImageAlphaPremultiply(Image *image)
     ImageFormat(image, prevFormat);
 }
 
+
+
 #if defined(SUPPORT_IMAGE_MANIPULATION)
 // Crop an image to area defined by a rectangle
 // NOTE: Security checks are performed in case rectangle goes out of bounds