I want to take a screenshot of a MapView and save to photos
This is the used source:
- (IBAction)screenshot:(id)sender {
if ([[UIScreen mainScreen] respondsToSelector:#selector(scale)])
UIGraphicsBeginImageContextWithOptions(mapView.frame.size, NO, [UIScreen mainScreen].scale);
else
UIGraphicsBeginImageContext(mapView.frame.size);
[mapView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
}
The action is successful, but the photo looks like this here
MapView Screenshot
I do not know what is wrong. I've already tried some codes. All with the same result. If I make a screenshot of the entire view, the map also looks like the picture above.
Does anyone have any idea or can help me?
EDIT:
- (UIImage*) ImageFromMapView
{
UIGraphicsBeginImageContext(self.frame.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
//[[[yourmapView.layer sublayers] objectAtIndex:1] renderInContext:UIGraphicsGetCurrentContext()]; try this upper fails
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
Try using UIGraphicsBeginImageContextWithOptions instead of UIGraphicsBeginImageContext:
UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0.0);
Note: Starting from iOS 4, UIGraphicsBeginImageContextWithOptions allows you to provide with a scale factor. A scale factor of zero sets it to the scale factor of the device's main screen. This enables you to get the sharpest, highest-resolustion snapshot of the display, including a Retina Display.
Related
I am trying to take a retina screenshot programmatically and I have tried every approach found online, but I was not able to get the screenshot to be retina.
I understand the following private API:
UIGetScreenImage();
cannot be used as Apple will reject your app. However, this method returns exactly what I need (640x960 screenshot of the screen).
I have tried this method on my iPhone 4 as well as the iPhone 4 simulator on retina hardware, but the resulting image is always 320x480.
-(UIImage *)captureView
{
AppDelegate *appdelegate = [[UIApplication sharedApplication]delegate];
if ([[UIScreen mainScreen] respondsToSelector:#selector(scale)])
UIGraphicsBeginImageContextWithOptions(appdelegate.window.bounds.size, NO, 0.0);
else
UIGraphicsBeginImageContext(appdelegate.window.bounds.size);
[appdelegate.window.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSLog(#"SIZE: %#", NSStringFromCGSize(image.size));
NSLog(#"scale: %f", [UIScreen mainScreen].scale);
return image;
}
I have also tried the Apple recommended way:
- (UIImage*)screenshot
{
// Create a graphics context with the target size
// On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
// On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
CGSize imageSize = [[UIScreen mainScreen] bounds].size;
if (NULL != UIGraphicsBeginImageContextWithOptions)
UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
else
UIGraphicsBeginImageContext(imageSize);
CGContextRef context = UIGraphicsGetCurrentContext();
// Iterate over every window from back to front
for (UIWindow *window in [[UIApplication sharedApplication] windows])
{
if (![window respondsToSelector:#selector(screen)] || [window screen] == [UIScreen mainScreen])
{
// -renderInContext: renders in the coordinate space of the layer,
// so we must first apply the layer's geometry to the graphics context
CGContextSaveGState(context);
// Center the context around the window's anchor point
CGContextTranslateCTM(context, [window center].x, [window center].y);
// Apply the window's transform about the anchor point
CGContextConcatCTM(context, [window transform]);
// Offset by the portion of the bounds left of and above the anchor point
CGContextTranslateCTM(context,
-[window bounds].size.width * [[window layer] anchorPoint].x,
-[window bounds].size.height * [[window layer] anchorPoint].y);
// Render the layer hierarchy to the current context
[[window layer] renderInContext:context];
// Restore the context
CGContextRestoreGState(context);
}
}
// Retrieve the screenshot image
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSLog(#"Size: %#", NSStringFromCGSize(image.size));
return image;
}
But it also returns a non retina image:
2012-12-23 19:57:45.205 PostCard[3351:707] size: {320, 480}
Is there something obvious I'm missing? How come there methods that are suppose to take retina screenshot return me non retina screenshots?
Thanks in advance!
I don't see anything wrong in your code. Apart from image.size, have you tried logging image.scale? Is it 1 or 2? If it's 2, it is actually a retina image.
UIImage.scale represents the scale of the image. So an image with UIImage.size being 320×480 and UIImage.scale being 2 has an actual size of 640×960. From Apple's doc:
If you multiply the logical size of the image (stored in the size property) by the value in this property, you get the dimensions of the image in pixels.
It's the same idea as when you load an image into a UIImage with the #2x modifier. For example:
a.png (100×80) => size=100×80 scale=1
b#2x.png (200×160) => size=100×80 scale=2
I'm having something really weird going, I'm adding caption to an image and everything works fine on simulator but on the device itself the font is really small...
I have a problem when using this code :
-(UIImage*) drawTextOnPic:(NSString*) bottomText
inImage:(UIImage*) image
{
UIFont *font = [UIFont boldSystemFontOfSize:48];
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
CGRect = CGRectMake(10.0f,10.0f,image.size.width-20.0f, image.size.height);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetShadow(context, CGSizeMake(2.5f, 2.5f), 5.0f);
[[UIColor whiteColor] set];
[bottomText drawInRect:CGRectIntegral(rect) withFont:font lineBreakMode:UILineBreakModeClip alignment:UITextAlignmentCenter];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
Does someone know why it works only on simulator as I expected? BTW, I'm using the SDK for iOS6, Can it be something there?
Is it something with the retina display? How to fix that?
When you call UIGraphicsBeginImageContext, you should be using the extended call to pass in screen scale, like this:
UIGraphicsBeginImageContextWithOptions(image.size, YES, [[UIScreen mainScreen] scale]);
That will create the image context at the scale of your screen. Note that the second argument, here YES, is whether or not you need the image to be opaque. If there's transparency in your image, set this to NO.
I choose the default font size (on my case it's 48) and then checked the image size according to some ref size (in my case 640x480), I did that by sqrtf(area(a)/area(ref)) then multiply this result on font size.
That's the only way it works for me.
Hope that would help others...
// Drawing text on image
+ (UIImage*) drawText:(NSString*)text withColor:(UIColor *) textColor inImage:(UIImage*)image atPoint:(CGPoint)point {
UIFont *font = [UIFont boldSystemFontOfSize:12];
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
[textColor set];
[text drawInRect:CGRectIntegral(rect) withFont:font];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
I got this code to be able to take a screenshot of the view.
UIGraphicsBeginImageContext(scrollView.bounds.size);
[scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData * data = UIImagePNGRepresentation(image);
However, even if I set the context to be 320x480, parts of the scroll view are still not shown. The view that the scrollview manages can perfectly fit within the 320x480 frame, but parts of it are covered by the status bar, navBar and TabBar.
I would like to take full screen (320x480) screenshot of the view with the parts of the view, covered by status bar, TabBar and NavBar visible. Any pointers on how to do this?
An extra question, which may be related: the resulting image is using x1 scale, and looks very blurry on the retina display, which scales takes a larger image and scales it down. This means I'll need to render the 640x960 screenshot to reproduce the original crisp quality. How would I go about doing that?
Thank you!
I found the following on this site: http://www.icodeblog.com/2009/07/27/1188/
UIGraphicsBeginImageContext(YourView.frame.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
You may also want to check out this (Apple's example of how to make a screenshot): http://developer.apple.com/library/ios/#qa/qa1703/_index.html
First make a screenshot of the whole screen:
// Create a graphics context with the target size
// On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
// On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
CGSize imageSize = [[UIScreen mainScreen] bounds].size;
if (NULL != UIGraphicsBeginImageContextWithOptions)
UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);
else
UIGraphicsBeginImageContext(imageSize);
CGContextRef context = UIGraphicsGetCurrentContext();
// Iterate over every window from back to front
for (UIWindow *window in [[UIApplication sharedApplication] windows])
{
if (![window respondsToSelector:#selector(screen)] || [window screen] == [UIScreen mainScreen])
{
// -renderInContext: renders in the coordinate space of the layer,
// so we must first apply the layer's geometry to the graphics context
CGContextSaveGState(context);
// Center the context around the window's anchor point
CGContextTranslateCTM(context, [window center].x, [window center].y);
// Apply the window's transform about the anchor point
CGContextConcatCTM(context, [window transform]);
// Offset by the portion of the bounds left of and above the anchor point
CGContextTranslateCTM(context,
-[window bounds].size.width * [[window layer] anchorPoint].x,
-[window bounds].size.height * [[window layer] anchorPoint].y);
// Render the layer hierarchy to the current context
[[window layer] renderInContext:context];
// Restore the context
CGContextRestoreGState(context);
}
}
// Retrieve the screenshot image
UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();
Then crop it to the right size
CGImageRef subImageRef = CGImageCreateWithImageInRect(screenshot.CGImage, rect);
CGRect smallBounds = CGRectMake(0, 64, 320, 372); //You should remove the hard coded numbers
UIGraphicsBeginImageContext(smallBounds.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, smallBounds, subImageRef);
UIImage* cropped = [UIImage imageWithCGImage:subImageRef];
UIGraphicsEndImageContext();
I've got two UIImageViews, I've managed to merge and save them. But I want the overlaying image to scale and position relatively with the scale of the chosen image. So that the UIImageView that you see on the screen looks the same as the UIImageView which it saves.
- (UIImage *)combineImages{
UIGraphicsBeginImageContext(CGSizeMake(theimageView.image.size.width,theimageView.image.size.height));
// Draw image1
[theimageView.image drawInRect:CGRectMake(0,0, theimageView.image.size.width,theimageView.image.size.height)];
// Draw image2
[Birdie.image drawInRect:CGRectMake(Birdie.center.x, Birdie.center.y, (theimageView.image.size.width / 2), (theimageView.image.size.height / 2))];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resultingImage;
}
theImageView and Birdie are the two UIImageViews.
Thanks in advanced!
Please Try this,
- (UIImage *)combineImages{
// Draw image1
[theimageView.image drawInRect:CGRectMake(0,0, theimageView.image.size.width,theimageView.image.size.height)];
// Draw image2
[Birdie.image drawInRect:CGRectMake(Birdie.frame.origin.x, Birdie.frame.origin.y, Birdie.frame.size.width, Birdie.frame.size.height)];
//have you added Birdie over theimageView if not than do this. If your size is already set as you want then there is no need for above two lines of drawInRect.
UIGraphicsBeginImageContext(theimageView.bounds.size);
[theimageView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resultingImage;
}
Thanks,
I use the same big images in a tableView and detailView.
Need to make imageView filled in 40x40 when an imags is showed in tableView, but stretched on a half of a screen. I played with several properties but have no positive result:
[cell.imageView setBounds:CGRectMake(0, 0, 50, 50)];
[cell.imageView setClipsToBounds:NO];
[cell.imageView setFrame:CGRectMake(0, 0, 50, 50)];
[cell.imageView setContentMode:UIViewContentModeScaleAspectFill];
I am using SDK 3.0 with build in "Cell Objects in Predefined Styles".
I put Ben's code as an extension in my NS-Extensions file so that I can tell any image to make a thumbnail of itself, as in:
UIImage *bigImage = [UIImage imageNamed:#"yourImage.png"];
UIImage *thumb = [bigImage makeThumbnailOfSize:CGSizeMake(50,50)];
Here is .h file:
#interface UIImage (PhoenixMaster)
- (UIImage *) makeThumbnailOfSize:(CGSize)size;
#end
and then in the NS-Extensions.m file:
#implementation UIImage (PhoenixMaster)
- (UIImage *) makeThumbnailOfSize:(CGSize)size
{
UIGraphicsBeginImageContextWithOptions(size, NO, UIScreen.mainScreen.scale);
// draw scaled image into thumbnail context
[self drawInRect:CGRectMake(0, 0, size.width, size.height)];
UIImage *newThumbnail = UIGraphicsGetImageFromCurrentImageContext();
// pop the context
UIGraphicsEndImageContext();
if(newThumbnail == nil)
NSLog(#"could not scale image");
return newThumbnail;
}
#end
I cache a thumbnail version since using large images scaled down on the fly uses too much memory.
Here's my thumbnail code:
- (UIImage *)thumbnailOfSize:(CGSize)size {
if( self.previewThumbnail )
return self.previewThumbnail; // returned cached thumbnail
UIGraphicsBeginImageContext(size);
// draw scaled image into thumbnail context
[self.preview drawInRect:CGRectMake(0, 0, size.width, size.height)];
UIImage *newThumbnail = UIGraphicsGetImageFromCurrentImageContext();
// pop the context
UIGraphicsEndImageContext();
if(newThumbnail == nil)
NSLog(#"could not scale image");
self.previewThumbnail = newThumbnail;
return self.previewThumbnail;
}
Just make sure you properly clear the cached thumbnail if you change your original image (self.preview in my case).
I have mine wrapped in a UIView and use this code:
imageView.contentMode = UIViewContentModeScaleAspectFit;
imageView.autoresizingMask = UIViewAutoresizingFlexibleWidth |UIViewAutoresizingFlexibleHeight;
[self addSubview:imageView];
imageView.frame = self.bounds;
(self is the wrapper UIView, with the dimensions I want - I use AsyncImageView).
I thought Ben Lachman's suggestion of generating thumbnails in advance rather than on the fly was smart, so I adapted his code so it could handle a whole array and to make it more portable (no hard-coded property names).
- (NSArray *)arrayOfThumbnailsOfSize:(CGSize)size fromArray:(NSArray*)original {
NSMutableArray *temp = [NSMutableArray arrayWithCapacity:[original count]];
for(UIImage *image in original){
UIGraphicsBeginImageContext(size);
[image drawInRect:CGRectMake(0,0,size.width,size.height)];
UIImage *thumb = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[temp addObject:thumb];
}
return [NSArray arrayWithArray:temp];
}
you might be able to use this?
yourTableViewController.rowImage = [UIImage imageNamed:#"yourImage.png"];
and/or
cell.image = yourTableViewController.rowImage;
and if your images are already 40x40 then you shouldn't have to worry about setting bounds and stuff... but, i'm also new to this, so, i wouldn't know, haven't played around with Table View row/cell images much
hope this helps.
I was able to make this work using interface builder and a tableviewcell. You can set the "Mode" properties for an image view to "Aspect Fit". I'm not sure how to do this programatically.
Try setting UIImageView.autoresizesSubviews and/or UIImageView.contentStretch.