after calling malloc need to set 0 to the buffer in

CoreGraphicsAdditions.c

include <string.h>

...

CGContextRef CKBitmapContextAndDataCreate(CGSize size, void ** data) {
...

   memset(bitmapData, 0, size.width*size.height*4 );

I am getting this error : library not found for -lImageAdditions

Also : libImageAdditions.a not found

In CKImageCreateByTrimmingTransparency(CGImageRef image, CKImageTrimmingSides sides) a UInt32 array is used instead of an unsigned char array for the bitmap data received from context. It can cause big endian related issues. for example a pixel, when addressed via the UInt32 array will look like this
in the following debug code I have written

(data is defined as unsigned char* data)

            int r = data[4*y*width+4*x+0];
            int g = data[4*y*width+4*x+1];
            int b = data[4*y*width+4*x+2];
            int alpha = data[4*y*width+4*x+3];

            int xx = ((UInt32*)data)[y*width+x];

in the debugger the values will be as follows

        int xx = 0xff01ff00

while the components when addressed via rgba (alpha premultiplied last) are

int r = 0
int g = 0xff
int b = 0x1
int alpha = 0xff

As you can see, in images that have any value of Red the function will be correct, (since most often pixels that have an alpha=0 are also fully zeroed) but in case of almost pure green, (like my test case) it will be incorrect

The Fix is:

redefine

unsigned char * data = bitmapData;

and in the said function use the following code in the scan loops

            int alpha = data[4*y*width+4*x+3];

            if (alpha != 0) 
            {
                left = x;
                goto SCAN_TOP;
            }

Thanks for your work on the lib. Hope this helps

Please help me to solve this

I got this error message when use this additions on device 3.0 - 3.2, how to solve this issue?

Program received signal: “EXC_BAD_ACCESS”.
Not safe to look up objc runtime data.
Not safe to look up objc runtime data.
Not safe to look up objc runtime data.

thanks.

You should release the context...
return CGBitmapContextCreateImage(context);

Should be something like ...
CGImageRef image = CGBitmapContextCreateImage(context);
CGContextRelease(context);
return image;

When finding a scale to use to resize an image, you should use the image's internal scale and not the screen's scale. If an image is only available @1x and the screen is @2x, this could have unintended side-effects.

Thanks for this library. However, I seem to have issues using the trimming utility. I assign a UIColor with RGB colour space, but it doesn't actually trim the image.

Here's an example of an image I am trying to trim:

I'm wanting to trim the black borders on the top and bottom, so I set the UIColor to [UIColor colorWithRed:0 green:0 blue:0 alpha:1]] but I am returned the exact same image, nothing is being trimmed.