CGPattern does not tile/repeat

[adein]

Issue Description

Filling with a CGPattern does not result in the pattern being repeated through the filled area.

Reproduction Steps

1. Create a CGPattern that is smaller than the area to be filled.
2. Set the pattern as the fill pattern using CGContextSetFillPattern.
3. Fill an area using CGContextFillRect.

Expected Behavior

If a CGPattern is less than the size of the area to be filled, the pattern should be tiled in the filled space.

Observed Behavior

The pattern is only drawn once in the filled area.

Pull Request, Test Case, or Sample Code

    // White background
    CGContextSetFillColorWithColor(context, [UIColor whiteColor].CGColor);
    CGContextFillRect(context, CGRectMake(0, 0, maxWidth, maxHeight));

    // Create a base pattern color space
    CGContextSaveGState(context);
    CGColorSpaceRef colorSpace = CGColorSpaceCreatePattern(NULL);
    CGContextSetFillColorSpace(context, colorSpace);
    CGColorSpaceRelease(colorSpace);

    // Create the pattern
    static const CGPatternCallbacks callbacks = { 0, &_DrawCustomPattern, NULL };
    CGFloat alpha = 1;
    CGPatternRef pattern = CGPatternCreate(
        NULL, rect, CGAffineTransformIdentity, c_PatternSize, c_PatternSize, kCGPatternTilingConstantSpacing, true, &callbacks);
    CGContextSetFillPattern(context, pattern, &alpha);
    CGPatternRelease(pattern);

    // Fill using the pattern
    CGContextFillRect(context, rect);
    CGContextRestoreGState(context);

void _DrawCustomPattern(void* info, CGContextRef context) {
    // Draw a circle inset from the pattern size
    CGRect circleRect = CGRectMake(0, 0, c_PatternSize, c_PatternSize);
    circleRect = CGRectInset(circleRect, 4, 4);
    CGContextFillEllipseInRect(context, circleRect);
    CGContextStrokeEllipseInRect(context, circleRect);
}

[adein]

I believe I have found the fix for this issue, and will submit a pull request for it after some more testing.