1 files changed, 53 insertions, 0 deletions
diff --git a/macosx/HBImageUtilities.m b/macosx/HBImageUtilities.m
index 07530d815..d5858c60d 100644
--- a/macosx/HBImageUtilities.m
+++ b/macosx/HBImageUtilities.m
@@ -8,6 +8,59 @@
 #import <Cocoa/Cocoa.h>
 #include "hb.h"
 
+CGImageRef CreateScaledCGImageFromCGImage(CGImageRef image, CGFloat thumbnailHeight)
+{
+    // Create the bitmap context
+    CGContextRef    context = NULL;
+    void *          bitmapData;
+    int             bitmapByteCount;
+    int             bitmapBytesPerRow;
+
+    // Get image width, height. We'll use the entire image.
+    int width = (CGFloat)CGImageGetWidth(image) / (CGFloat)CGImageGetHeight(image) * thumbnailHeight;
+    int height = thumbnailHeight;
+
+    // Declare the number of bytes per row. Each pixel in the bitmap in this
+    // example is represented by 4 bytes; 8 bits each of red, green, blue, and
+    // alpha.
+    bitmapBytesPerRow   = (width * 4);
+    bitmapByteCount     = (bitmapBytesPerRow * height);
+
+    // Allocate memory for image data. This is the destination in memory
+    // where any drawing to the bitmap context will be rendered.
+    bitmapData = malloc(bitmapByteCount);
+    if (bitmapData == NULL)
+    {
+        return nil;
+    }
+
+    // Create the bitmap context. We want pre-multiplied ARGB, 8-bits
+    // per component. Regardless of what the source image format is
+    // (CMYK, Grayscale, and so on) it will be converted over to the format
+    // specified here by CGBitmapContextCreate.
+    CGColorSpaceRef colorspace = CGImageGetColorSpace(image);
+    context = CGBitmapContextCreate (bitmapData,width,height,8,bitmapBytesPerRow,
+                                     colorspace,kCGImageAlphaNoneSkipFirst);
+
+    if (context == NULL)
+    {
+        // error creating context
+        return nil;
+    }
+
+    // Draw the image to the bitmap context. Once we draw, the memory
+    // allocated for the context for rendering will then contain the
+    // raw image data in the specified color space.
+    CGContextDrawImage(context, CGRectMake(0,0,width, height), image);
+
+    CGImageRef imgRef = CGBitmapContextCreateImage(context);
+    CGContextRelease(context);
+    free(bitmapData);
+
+    return imgRef;
+}
+
+
 CGImageRef CGImageRotated(CGImageRef imgRef, CGFloat angle, BOOL flipped) CF_RETURNS_RETAINED
 {
     CGFloat angleInRadians = angle * (M_PI / 180);