我正在开发一个 iPhone 应用程序，我可以用相机拍照。此后应该可以将图像切片为各种形状 - 最重要的是三角形。任何人都可以给我一个正确方向的观点或示例等。我已经可以将其切成正方形，但不能切成三角形。
（更新）为了创建方形切片，我使用了以下代码片段
CGRect ClippedRect= CGRectMake(0, 150, 320.0, 230.0);//example numbers
CGImageRef imageRef = CGImageCreateWithImageInRect([OriginalUIImage CGImage], ClippedRect);
UIImage *resultUIImage=[[UIImage alloc]initWithCGImage:imageRef];
所有帮助
感谢
解决了：
我采用了屏蔽 uiimage 的方法。所以策略是 1. 用相机和秤拍照。 2. 让用户在 uiimageview 中绘制一个图形并用黑色填充它，然后从中创建一个 UIImage。 3. 使用用户生成的图像遮盖来自相机的图像。
为了屏蔽图像，我使用 http://www 中的以下方法.developers-life.com/resize-and-mask-an-image.html
- (UIImage*) maskImage:(UIImage *)image {
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
UIImage *maskImage = [UIImage imageNamed:@"mask.png"];
CGImageRef maskImageRef = [maskImage CGImage];
// create a bitmap graphics context the size of the image
CGContextRef mainViewContentContext = CGBitmapContextCreate (NULL, maskImage.size.width, maskImage.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
if (mainViewContentContext==NULL)
return NULL;
CGFloat ratio = 0;
ratio = maskImage.size.width/ image.size.width;
if(ratio * image.size.height < maskImage.size.height) {
ratio = maskImage.size.height/ image.size.height;
}
CGRect rect1 = {{0, 0}, {maskImage.size.width, maskImage.size.height}};
CGRect rect2 = {{-((image.size.width*ratio)-maskImage.size.width)/2 , -((image.size.height*ratio)-maskImage.size.height)/2}, {image.size.width*ratio, image.size.height*ratio}};
CGContextClipToMask(mainViewContentContext, rect1, maskImageRef);
CGContextDrawImage(mainViewContentContext, rect2, image.CGImage);
// Create CGImageRef of the main view bitmap content, and then
// release that bitmap context
CGImageRef newImage = CGBitmapContextCreateImage(mainViewContentContext);
CGContextRelease(mainViewContentContext);
UIImage *theImage = [UIImage imageWithCGImage:newImage];
CGImageRelease(newImage);
// return the image
return theImage;
}
感谢您的所有帮助
I am working on a iPhone app where I take a picture with the camera. Hereafter it should be possible to slice the image in various shapes - most important triangles. Can anyone give me a point in the right direction or examples etc. I have made it possible to slice into squares but not triangles.
(Updated)For creating the squared slices I used the following code snippets
CGRect ClippedRect= CGRectMake(0, 150, 320.0, 230.0);//example numbers
CGImageRef imageRef = CGImageCreateWithImageInRect([OriginalUIImage CGImage], ClippedRect);
UIImage *resultUIImage=[[UIImage alloc]initWithCGImage:imageRef];
All help is appreciated
Regards
SOLVED:
I went with the method of masking the uiimage. So the strategy is that 1. Take picture from camera and scale. 2. Let the user draw a figure in a uiimageview and fill it with black color and the create a UIImage from this. 3. Mask the image from the camera with the user generated image.
For masking the image I use the following method from http://www.developers-life.com/resize-and-mask-an-image.html
- (UIImage*) maskImage:(UIImage *)image {
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
UIImage *maskImage = [UIImage imageNamed:@"mask.png"];
CGImageRef maskImageRef = [maskImage CGImage];
// create a bitmap graphics context the size of the image
CGContextRef mainViewContentContext = CGBitmapContextCreate (NULL, maskImage.size.width, maskImage.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
if (mainViewContentContext==NULL)
return NULL;
CGFloat ratio = 0;
ratio = maskImage.size.width/ image.size.width;
if(ratio * image.size.height < maskImage.size.height) {
ratio = maskImage.size.height/ image.size.height;
}
CGRect rect1 = {{0, 0}, {maskImage.size.width, maskImage.size.height}};
CGRect rect2 = {{-((image.size.width*ratio)-maskImage.size.width)/2 , -((image.size.height*ratio)-maskImage.size.height)/2}, {image.size.width*ratio, image.size.height*ratio}};
CGContextClipToMask(mainViewContentContext, rect1, maskImageRef);
CGContextDrawImage(mainViewContentContext, rect2, image.CGImage);
// Create CGImageRef of the main view bitmap content, and then
// release that bitmap context
CGImageRef newImage = CGBitmapContextCreateImage(mainViewContentContext);
CGContextRelease(mainViewContentContext);
UIImage *theImage = [UIImage imageWithCGImage:newImage];
CGImageRelease(newImage);
// return the image
return theImage;
}
Thank you for all the help
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评论（2）
尝试这样的事情：
http://iosdevelopertips.com/cocoa/how-to-mask- an-image.html
如果我的解释正确的话，只需制作一个黑色图像作为蒙版并将其应用到图像上即可。
Try something like this:
http://iosdevelopertips.com/cocoa/how-to-mask-an-image.html
Simply make a black image as your mask and apply it to the image, if i get this explanation right.
您应该能够使用这种方法：使用 UIGraphicsBeginImageContextWithOptions （您也可以使用 CoreGraphics 等效项，但需要更多工作），然后创建所需形状的贝塞尔曲线路径，调用 [yourBezierPath addClip]，然后在该上下文中绘制图像。然后，您可以使用 UIGraphicsGetImageFromCurrentImageContext。请务必随后调用
UIGraphicsEndImageContext()。有关使用UIGraphicsBeginImageContextWithOptions创建图像的信息，请参阅此问题 。You should be able to use this approach: Create a new image using UIGraphicsBeginImageContextWithOptions (you could also use the CoreGraphics equivalent but is much more work), then create a bezier path of the shape you want, call [yourBezierPath addClip] and then draw your image in that context. You can then get the resulting image using UIGraphicsGetImageFromCurrentImageContext. Be sure to call
UIGraphicsEndImageContext()afterwards. See this question for creating an image withUIGraphicsBeginImageContextWithOptions.