I'm trying to draw image using UIImage's drawInRect: method. Here is the code:
UIImage *image = [UIImage imageNamed:#"OrangeBadge.png"];
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];
UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
The problem is that the resulting image is blurry. Here is the resulting image (on the right side) compared to the source image (on the left side):
I've tried both CGContextSetAllowsAntialiasing(UIGraphicsGetCurrentContext(), NO) CGContextSetShouldAntialias(UIGraphicsGetCurrentContext(), NO) but this did not solve the problem.
Any ideas?
Thanks in advance.
If you are developing on a retina device, possibly the issue is related to the resolution of your graphics context. Would you try with:
UIGraphicsBeginImageContextWithOptions(size, NO, 2.0f);
This will enable retina resolution. Also, your image should be available at #2x resolution for this to work.
If you want to support non-retina devices as well, you can use:
if ([UIScreen instancesRespondToSelector:#selector(scale)]) {
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0f);
} else {
UIGraphicsBeginImageContext(newSize);
}
Related
This is my Transparent image (Front image).
This is my selected image (Back Image).
I am giving gestures to the back image.
How can i save my image after using of pan, pinch, rotate gestures.
Present am able to combine both images but back image is saving as it is like (below image)
Using this code
CGSize newSize = CGSizeMake(640, 960);
UIGraphicsBeginImageContext( newSize);
[backImage.image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
[frontImage.image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:1.0];
finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(finalImage, nil, nil, nil);
I think i should handle this two lines but i don't know how to handle.
[backImage.image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
[frontImage.image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:1.0];
Can any one help me will highly appreciated.
Thank you.
Please find the below code to get snapshot your imageview.
UIGraphicsBeginImageContextWithOptions(yourImageViewToSnapShot.bounds.size, NO, 0.0);
[yourImageViewToSnapShot.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
I am having problem with UIImage resizing, image masking is working fine but after applying mask UIImage is starched, the problem is with scaling as image is not scaled properly.
CCClippingNode *clippingNode = [[CCClippingNode alloc] initWithStencil:pMaskingFrame ];
pTobeMasked.scaleX = (float)pMaskingFrame.contentSize.width / (float)pTobeMasked.contentSize.width;
pTobeMasked.scaleY = (float)pMaskingFrame.contentSize.height / (float)pTobeMasked.contentSize.height;
clippingNode.alphaThreshold = 0;
[pContainerNode addChild:clippingNode];
pTobeMasked.position = ccp(pMaskingFrame.position.x, pMaskingFrame.position.y);
[clippingNode addChild:pTobeMasked];
One of my project I have used below function to resize an image;
/*
method parameters definition
image : original image to be resized
size : new size
*/
+ (UIImage*)resizeImage:(UIImage *)image size:(CGSize)size
{
UIGraphicsBeginImageContext(size);
[image drawInRect:CGRectMake(0, 0, size.width, size.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
//here is the scaled image which has been changed to the size specified
UIGraphicsEndImageContext();
return newImage;
}
This will work like a charm. It's similar to the already posted answer, but it has some more options:
+(UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
//UIGraphicsBeginImageContext(newSize);
// In next line, pass 0.0 to use the current device's pixel scaling factor (and thus account for Retina resolution).
// Pass 1.0 to force exact pixel size.
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
I am not the best graphic designer, but need to setup few icons. I made them with gimp with options like Border, etc. All are primary designed in 1000x1000px and used in objective-c code in UIImageView.
I am wondering why resized icon look that terrible. Any suggestions?
In app:
http://s14.postimg.org/k2g9uayld/Screen_Shot_2014_12_18_at_11_22_53.png
http://s14.postimg.org/biwvwjq8x/Screen_Shot_2014_12_18_at_11_23_02.png
Original image:
Can't Post more than 2 links so: s17.postimg.org/qgi4p80an/fav.png
I dont think that matters but
UIImage *image = [UIImage imageNamed:#"fav.png"];
image = [UIImage imageWithCGImage:[image CGImage] scale:25 orientation:UIImageOrientationUp];
self.navigationItem.titleView = [[UIImageView alloc] initWithImage:image];
But one of images has been set up in storyboard and effect is the same.
[self.favO.layer setMinificationFilter:kCAFilterTrilinear];
[self.favO setImage:[self resizeImage:[UIImage imageNamed:#"fav.png"] newSize:CGSizeMake(35,35)]
forState:UIControlStateNormal];
- (UIImage *)resizeImage:(UIImage*)image newSize:(CGSize)newSize {
CGRect newRect = CGRectIntegral(CGRectMake(0, 0, newSize.width, newSize.height));
CGImageRef imageRef = image.CGImage;
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, newSize.height);
CGContextConcatCTM(context, flipVertical);
CGContextDrawImage(context, newRect, imageRef);
CGImageRef newImageRef = CGBitmapContextCreateImage(context);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
CGImageRelease(newImageRef);
UIGraphicsEndImageContext();
return newImage;
}
This fixed problem. This problem occurs while UIImageView takes care of resizing.
To avoid this kind of behavior I suggest you make SVGs instead of png files. Using the lib SVGKit you can then resize it to your heart content. Since SVG format is a vectorial format there won't be any loss in your scaling.
https://github.com/SVGKit/SVGKit
EDIT:
To add up to this solution, your PNG file at 1000X1000px must be really heavy, on the other hand a SVG file is a text file so it makes it very lightweight
My code:
-(UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize
{
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
The first parameter is image which is screen shot my view controller.
The second parameter newSize is actually smaller than the image size which follows the aspect ratio also. But the image is looks good but the text(UILabel) are some what blur.
How can i solve this any idea?
Assuming newSize is in points:
UIGraphicsBeginImageContextWithOptions(newSize, NO, image.scale);
I am not sure whether I can improve image quality but following code displays very poor image quality in PDF. I know its standard code to generate images from view but is there anything I could do to specify image quality or improve it?
- (void)renderView:(UIView*)view {
UIGraphicsBeginImageContext(view.frame.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewAsImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[viewAsImage drawInRect:rect];
}
You probably need to create a graphics context with a scale of 2 (retina) instead of the default 1. To do so, use UIGraphicsBeginImageContextWithOptions(view.frame.size, YES, 0.0);. This will create an image context with an opaque target (you can set the second parameter to NO if you're rendering a transparent image) and with a scale factor of your device's main screen.
Double the size!
- (void)renderView:(UIView*)view {
CGSize newSize = view.frame.size;
newSize.width = newSize.width * [UIScreen mainScreen].nativeScale;
newSize.height = newSize.height * [UIScreen mainScreen].nativeScale;
UIGraphicsBeginImageContext(newSize);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewAsImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[viewAsImage drawInRect:rect];
}