Wrong code in YYImageCoder.m

[wysaid]

The code below in YYImageCode.m at line 1405-1415
The buffer named "tmp" is never used, please fix.
And the code segment is never run...

`
if (iter.x_offset != 0 || iter.y_offset != 0) {

void *tmp = calloc(1, destLength);

if (tmp) {

    vImage_Buffer src = {destBytes, canvasHeight, canvasWidth, bytesPerRow};

    vImage_Buffer dest = {destBytes, canvasHeight, canvasWidth, bytesPerRow};

    vImage_CGAffineTransform transform = {1, 0, 0, 1, iter.x_offset, -iter.y_offset};

    uint8_t backColor[4] = {0};

    vImageAffineWarpCG_ARGB8888(&src, &dest, NULL, &transform, backColor, kvImageBackgroundColorFill);

    memcpy(destBytes, tmp, destLength);

    free(tmp);

}

}

`

[wysaid]

And also there's a waste of memory in the alignment calculation.
code:

hasAlpha = config.input.has_alpha;
bitsPerComponent = 8;
bitsPerPixel = 32;
bytesPerRow = YYImageByteAlign(bitsPerPixel / 8 * canvasWidth, 32);

The image can have 3 or 4 channels. But you're not handling the two situations.
So if an image has no alpha channel, 25% of additional useless memory is allocated.

[ibireme]

Thanks~

1. The bug is fixed: b659f90
2. Core Animation prefer to use bgrA8888 (kCGBitmapByteOrder32Host | kCGImageAlphaPremultipliedFirst) data to display image, see also: https://github.com/path/FastImageCache#byte-alignment