Question

目前我正在使用基于GLpaint的绘图应用程序。保存当前屏幕对我来说是一种忙碌的痛苦。我有一个ViewController，在视图控制器的顶部我已经加载了我的UIIMageView和UIView（PaintingView）。现在看起来我正在绘制UIImageView的顶部。

我已设法通过此问题GLPaint save image获取当前的绘图。当我尝试捕捉当前的绘图时，我得到了我的绘图，但是黑屏。我想要的是我的背景图像（UIImageView）。我应该用UIImageView覆盖UIView吗？

Answer 1

您应该使用OpenGL加载图像，而不是UIKit（作为UIImageView）。否则，您只能将OpenGLView捕获为单个图像，并将UIKit视图捕获为不同的图像。

为此，您必须在GLpaint示例中提供的PaintingView类中的Texture中渲染图像，然后通过在绘图视图上绘制四边形来加载它。

Answer 2

我使用此代码从OpenGL中获取图像：

-(BOOL)iPhoneRetina{
    return ([[UIScreen mainScreen] respondsToSelector:@selector(displayLinkWithTarget:selector:)] && ([UIScreen mainScreen].scale == 2.0))?YES:NO;
}

void releasePixels(void *info, const void *data, size_t size) {
    free((void*)data);
}

-(UIImage *) glToUIImage{

    int imageWidth, imageHeight;

    int scale = [self iPhoneRetina]?2:1;

    imageWidth = self.frame.size.width*scale;
    imageHeight = self.frame.size.height*scale;

    NSInteger myDataLength = imageWidth * imageHeight * 4;

    // allocate array and read pixels into it.
    GLubyte *buffer = (GLubyte *) malloc(myDataLength);
    glReadPixels(0, 0, imageWidth, imageHeight, GL_RGBA, GL_UNSIGNED_BYTE, buffer);

    // make data provider with data.
    CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, buffer, myDataLength, releasePixels);

    // prep the ingredients
    int bitsPerComponent = 8;
    int bitsPerPixel = 32;
    int bytesPerRow = 4 * imageWidth;
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
    CGBitmapInfo bitmapInfo =  kCGImageAlphaPremultipliedLast;
    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;

    // make the cgimage

    CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);

    UIImage *myImage = [UIImage imageWithCGImage:imageRef scale:scale orientation:UIImageOrientationDownMirrored]; //Render image flipped, since OpenGL's data is mirrored

    CGImageRelease(imageRef);
    CGColorSpaceRelease(colorSpaceRef);

    CGDataProviderRelease(provider);

    return myImage;
}

这个将它与背景图像合并：

-(UIImage*)mergeImage:(UIImage*)image1 withImage:(UIImage*)image2{

    CGSize size = image1.size;

    UIGraphicsBeginImageContextWithOptions(size, NO, 0);

    [image1 drawAtPoint:CGPointMake(0.0f, 0.0f)];
    [image2 drawAtPoint:CGPointMake(0.0f, 0.0f)];

    UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return result;
}

这样的事情：

finalImage = [self mergeImage：BackgroundImage withImage [self glToUIImage]];

GLPaint保存功能（使用背景图像保存当前屏幕）

2 个答案: