我正在为客户开发增强现实应用程序。OpenGL 和 EAGL 部分已在 Unity 3D 中完成,并在我的应用程序中实现为视图。
我现在需要的是一个按钮,它可以捕捉 OpenGL 内容的屏幕截图,这是最后面的视图。
我尝试自己编写它,但是当我单击分配了 IBAction 的按钮时,它只保存了屏幕的 1/4(左下角)——尽管它确实将它保存到了相机胶卷中。
所以基本上,我怎样才能让它保存整个屏幕尺寸,而不是四分之一?
这是我的方法代码:
-(IBAction)tagBillede:(id)sender
{
UIImage *outputImage = nil;
CGRect s = CGRectMake(0, 0, 320, 480);
uint8_t *buffer = (uint8_t *) malloc(s.size.width * s.size.height * 4);
if (!buffer) goto error;
glReadPixels(0, 0, s.size.width, s.size.height, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, buffer, s.size.width * s.size.height * 4, NULL);
if (!ref) goto error;
CGImageRef iref = CGImageCreate(s.size.width, s.size.height, 8, 32, s.size.width * 4, CGColorSpaceCreateDeviceRGB(), kCGBitmapByteOrderDefault, ref, NULL, true, kCGRenderingIntentDefault);
if (!iref) goto error;
size_t width = CGImageGetWidth(iref);
size_t height = CGImageGetHeight(iref);
size_t length = width * height * 4;
uint32_t *pixels = (uint32_t *)malloc(length);
if (!pixels) goto error;
CGContextRef context = CGBitmapContextCreate(pixels, width, height, 8, width * 4,
CGImageGetColorSpace(iref), kCGImageAlphaNoneSkipFirst | kCGBitmapByteOrder32Big);
if (!context) goto error;
CGAffineTransform transform = CGAffineTransformIdentity;
transform = CGAffineTransformMakeTranslation(0.0f, height);
transform = CGAffineTransformScale(transform, 1.0, -1.0);
CGContextConcatCTM(context, transform);
CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, width, height), iref);
CGImageRef outputRef = CGBitmapContextCreateImage(context);
if (!outputRef) goto error;
outputImage = [UIImage imageWithCGImage: outputRef];
if (!outputImage) goto error;
CGDataProviderRelease(ref);
CGImageRelease(iref);
CGContextRelease(context);
CGImageRelease(outputRef);
free(pixels);
free(buffer);
UIImageWriteToSavedPhotosAlbum(outputImage, self, @selector(image: didFinishSavingWithError: contextInfo:), nil);
}