I’m trying to rotate a downloaded image that comes in PNG format with a 4:3 ratio that’s landscape.
I need the image rotated by 90 degrees so it’s portrait with the same dimensions.
I tried the .transform function which worked to start with but doesn’t anymore after adding a scrollView with a lot of settings to allow it to zoom and pan, Id rather not go down the route of editing the srollView content as it took a long time to get all the constrains to work properly to allow free zoom and pan.
After downloading my image I save it to app file. Then it’s loaded for display in another function.
Is it possible to rotate the downloaded file whilst saving so it can be retrieved in the correct way?
I found this in another post which I believe would work with the downloaded image, how can I change the orientation for my need?
func normalizedImage() -> UIImage
{
if (self.imageOrientation == UIImageOrientation.Up) {
return self;
}
UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale);
let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height)
self.drawInRect(rect)
let normalizedImage : UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext();
return normalizedImage;
}
If you display the UIImage in an image view you can try modifying the orientation.
It is basically the same UIImage but with a flag that is interpreted by UIImageView to rotate the image display.
let rotated = UIImage(cgImage: image.cgImage!, scale: 1, orientation: .right)
If you really want to save a new image to disk, you will need to actually redraw the image. Some info is already available here : How to Rotate a UIImage 90 degrees?
Related
Some context first:
I simply draw a UIImage to a PDFPage by subclassing PDFPage and overriding draw(with box,to context):
override func draw(with box: PDFDisplayBox, to context: CGContext) {
/* Draw image on PDF */
UIGraphicsPushContext(context)
// Change the PDF context to match the UIKit coordinate system.
context.translateBy(x: 0, y: pageBounds.height)
context.scaleBy(x: 1, y: -1)
context.interpolationQuality = .high
// The important line is here: drawing the image
self.myImage.draw(in: CGRect(x: leftMargin, y: topMargin, width: fittedImageSize.width, height: fittedImageSize.height))
}
where self.myImage contains a UIImage. So far so good.
The problem -> if I persist the image to save memory
If I init my CustomPDFPage with the original UIImage from memory --> I get a PDF file with a reasonable size, everything works well
However: if I persist the image using pngData(), then reload it using UIImage(contentsOfFile: url.path) for drawing, my PDF file is suddenly MUCH more heavier in size.
Writing the image to TMP:
let urlToWrite = tmpDir.appendingPathComponent(fileName)
do {
if let tmpData = image.png() {
DLog("TMPDATA SIZE = \(tmpData.count). Image dimensions = \(image.size) with scale = \(image.scale)")
}
try image.pngData()?.write(to: urlToWrite)
self.tmpImgURL = urlToWrite
} catch {
DLog("ERROR: could not write image to \(urlToWrite). Error is \(error)")
}
Reloading the image into memory:
var image = UIImage(contentsOfFile: self.tmpImgURL.path)
--> using that image to draw the PDF increases the PDF size dramatically.
Inspecting the UIImage size, the scale, and the bytes count of the image before writing to file and after reading to file give the exact same values.
So the reason behind this mess is because the user has the possibility to choose to reduce the quality of the image.
In that case, the source UIImage was an image recreated from jpegData (that was used to apply compression).
In short, calling UIImage.pngData() after UIImage.jpegData(...) is not a good idea. Just write directly the jpegData when the image might have been compressed.
I'm using fusuma project from github. If i select photo from library with fusuma and upload it to my server all is ok. But if i take photo from fusuma camera it rotates 90 degree. I tried to rotate it on php file but then it rotates all photos.
Is there any solution for fusuma project? (swift language)
For Swift 3
func fixOrientation(_image:UIImage) -> UIImage {
if (_image.imageOrientation == UIImageOrientation.up) {
return _image;
}
UIGraphicsBeginImageContextWithOptions(_image.size, false, _image.scale);
let rect = CGRect(x: 0, y: 0, width: _image.size.width, height: _image.size.height)
_image.draw(in: rect)
let normalizedImage : UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext();
return normalizedImage;
}
Fusuma doesn't support landscape orientations, so you'll need to assume every picture it takes is in portrait. See https://github.com/ytakzk/Fusuma/issues/50#issuecomment-225333675
I'm trying to draw a path on a high resolution image, that's nothing complicated for an iPhone but if I add shadow to my path everything lags. It lags only when I work on images with a certain resolution (2000 x 3000) even less.
The Storyboard vies are:
-Scroll View
-Image View
-Draw View
So I have the DrawingView on top of the ImageView when I need to draw.
So the ImageView and the DrawView (view.bounds.size) have the same resolution as the image (e.g. 2000 x 3000) (there's the problem).
I'm drawing on a view with a high resolution.
I'm not directly calling drawRect: but only calling setNeedsDisplay() inside touchesBegan() and touchesMoved() after doing some operations (path.moveToPoint, path.addCurveToPoint, array operations) and adding points to my array.
In drawRect: I essentially have:
override func drawRect(rect: CGRect) {
print(self.bounds.size)
UIColor.greenColor().setStroke()
path.lineCapStyle = .Round
path.lineJoinStyle = .Round
path.lineWidth = 60.0
context = UIGraphicsGetCurrentContext()!
CGContextAddPath(context, path.CGPath)
CGContextSetShadowWithColor(context, CGSizeZero, 14.0, UIColor.whiteColor().CGColor) // <-- with this shadow it lags a lot.
path.stroke()
}
My path is a UIBezierPath().
Any ideas to improve the speed?
Update:
I followed what #brimstone said. I now have ImageView with a lower resolution, but have to apply my drawn path to the high resolution image.
(I'm trying to hand crop an image with the path that the user draws)
In this code I already got my closed path:
let layer = CAShapeLayer()
layer.path = path.CGPath
self.imageToEditView.layer.mask = layer
UIGraphicsBeginImageContext(self.imageEdited.size)
self.imageToEditView.layer.renderInContext(UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
let croppedCGImage = CGImageCreateWithImageInRect(image.CGImage!, CGPathGetBoundingBox(path.CGPath))
let croppedImage = UIImage(CGImage: croppedCGImage!)
self.imageToEditView.image = croppedImage
self.imageToEditView.layer.mask = nil
imageToEditView.bounds.size = low resolution
imageEdited.size = high resolution
I need to set the hight resolution (I think) when i renderInContext. But how can I change the resolution of the imageView now?
Try downsizing it for the user to draw over (doesn't make a huge difference on small iPhone screens for user experience), then apply the edits to the high-res image.
To downsize images, either use UIImagePNGRepresentation, which may make your image sufficiently smaller, or (if you're still having memory issues), try using techniques in this tutorial and this answer to make it even smaller.
Then, you can take the content of what they've drawn and apply it to the high-res image.
Alternatively, look at high-res optimisation techniques by Apple: https://developer.apple.com/library/ios/documentation/2DDrawing/Conceptual/DrawingPrintingiOS/SupportingHiResScreensInViews/SupportingHiResScreensInViews.html
Working through a Core Graphics tutorial http://www.raywenderlich.com/76285/beginning-core-image-swift
Theres one part where you need to preserve the UIImageOrientation (of course!). However I'm noticing something VERY quirky and I'm not sure what the cause is.
Here is the code block
#IBAction func amountSliderValueChanged(sender: UISlider) {
let sliderValue = sender.value
filter.setValue(sliderValue, forKey: kCIInputIntensityKey)
let outputImage = filter.outputImage;
let cgimg = context.createCGImage(filter.outputImage, fromRect: filter.outputImage.extent())
let newImage = UIImage(CGImage: cgimg, scale:1, orientation: UIImageOrientation.UpMirrored)
// let newImage = UIImage(CGImage: cgimg)
println("New image is \(newImage)")
self.imageView.image = newImage
}
When I change the image to certain rotations, say Up, the image appears. However when I change to right or left it moves outside the UIImageView (and if I set the scale up really high I can see parts of it coming back on the screen).
I am not rotating the UIImageView, only the UIImage. Before, when I was doing this in Objective-C I never had this issue. I would just set the UIImage rotation and it would always be 0,0 in the UIImageView.
Using Swift (or perhaps something else?) seems to result in different behaviour.
Can you think of any reason why rotating the image moves it way from the its 0,0 of its UIImageView, and what I can do fix that?
Thanks!
I'm trying to get a bitmap of a UITextView's content. I'm able to get a bitmap of the UITextView's content that is currently on the screen with:
UIGraphicsBeginImageContext(myTextView.bounds.size);
[myTextView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
myImageView.image=resultingImage;
UIGraphicsEndImageContext();
But I want a bitmap of ALL the content, not just the content visible on the screen. Is this possible? Note that I don't want only the text of the UITextView, I want a bitmap of the content itself. I searched around and found how do do this in Android, with getDrawingCache, but couldn't find anything for objective c.
One way to do this is to make a copy of the UITextView and then resize the copy to it's content size (as long as the content size is bigger than the frame size).
In Swift it looks like this:
func imageFromTextView(textView: UITextView) -> UIImage {
// Make a copy of the textView first so that it can be resized
// without affecting the original.
let textViewCopy = UITextView(frame: textView.frame)
textViewCopy.attributedText = textView.attributedText
// resize if the contentView is larger than the frame
if textViewCopy.contentSize.height > textViewCopy.frame.height {
textViewCopy.frame = CGRect(origin: CGPointZero, size: textViewCopy.contentSize)
}
// draw the text view to an image
UIGraphicsBeginImageContextWithOptions(textViewCopy.bounds.size, false, UIScreen.mainScreen().scale)
textViewCopy.drawViewHierarchyInRect(textViewCopy.bounds, afterScreenUpdates: true)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image
}
This allows you to get an image of all of the content, even the part that in not visible without scrolling.
Notes
My somewhat more general answer is here.
The textViewCopy is only a copy of the frame and the attributed text. That should be enough to get a full image. However, if for some reason a more exact copy is needed, then one could do the following: (explanation)
let tempArchive = NSKeyedArchiver.archivedDataWithRootObject(textView)
let textViewCopy = NSKeyedUnarchiver.unarchiveObjectWithData(tempArchive) as! UITextView