Question

是的，我知道这听起来像是重复的...但我已经在他们的开发者页面上尝试了很多例子，甚至Apple的官方代码，这导致了iPhone 4S上的白色图像。 iPad 3。虽然在iPad 1和iPhone模拟器上运行良好。

传递给convertBitmapRGBA8ToUIImage的宽度和高度是实际像素，而不是UIKit'points'。即，在iPad 1上，它将是1024,768。在iPad 3上，它是2048,1536。

原始数据缓冲区是从glReadPixels读取的RGBA数据，并在传递给tweetMessage（）之前手动翻转。

- (UIImage *) convertBitmapRGBA8ToUIImage:(unsigned char *) buffer
                                withWidth:(int) width
                               withHeight:(int) height {

    CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, buffer, width * height * 4, NULL);
    CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
    CGImageRef iref = CGImageCreate(width, height, 8, 32, width * 4, colorspace, kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast, ref, NULL, true, kCGRenderingIntentDefault);

    float scale = 1.0f;
    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
    {
        scale = [[UIScreen mainScreen] scale];
    }

    UIGraphicsBeginImageContextWithOptions(CGSizeMake(width/scale, height/scale), NO, scale);
    CGContextRef cgcontext = UIGraphicsGetCurrentContext();

    CGContextSetBlendMode(cgcontext, kCGBlendModeCopy);

    // Image needs to be flipped BACK for CG
    CGContextTranslateCTM(cgcontext, 0, height/scale);
    CGContextScaleCTM(cgcontext, 1, -1);
    CGContextDrawImage(cgcontext, CGRectMake(0.0, 0.0, width/scale, height/scale), iref);

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    CFRelease(ref);
    CFRelease(colorspace);
    CGImageRelease(iref);

    return image;
}

- (void)tweetMessage:(const char *)message withURL:(const char *)url withImage:(unsigned char*)rawRGBAImage withWidth:(unsigned int)imageWidth withHeight:(unsigned int)imageHeight
{
    UIImage *tweetImage = nil;
    if (rawRGBAImage != nil)
    {
        // Convert raw data to UIImage
        tweetImage = [self convertBitmapRGBA8ToUIImage:rawRGBAImage withWidth:imageWidth withHeight:imageHeight];
    }
}

将原始RGBA转换为UIImage

0 个答案: