I'm drawing image with core graphics than i want to use it like a mask for another image, but just getting clear rectangular image.
take a look whats wrong with my cropping function ?
UIGraphicsBeginImageContext(CGSizeMake(self.bounds.size.width / 0.5, self.bounds.size.height / 0.5))
let imageCtx = UIGraphicsGetCurrentContext()
CGContextAddArc(imageCtx, CGFloat(self.frame.size.width ) , CGFloat(self.frame.size.height ), 158, 0, CGFloat(DegreesToRadians(Double(angle))) , 0)
CGContextSetLineWidth(imageCtx, 80)
CGContextDrawPath(imageCtx, .Stroke)
let myMask :CGImageRef = CGBitmapContextCreateImage(UIGraphicsGetCurrentContext())!
UIGraphicsEndImageContext()
let maskImage = UIImage(CGImage: myMask)
let testVideoPreview = UIImage(named: "alex")
guard let makedImage = testVideoPreview else {return}
var imageMaskOne: CGImageRef = CGImageMaskCreate(CGImageGetWidth(myMask), CGImageGetHeight(myMask), CGImageGetBitsPerComponent(myMask), CGImageGetBitsPerPixel(myMask), CGImageGetBytesPerRow(myMask), CGImageGetDataProvider(myMask), nil, // Decode is null
true)!
let masked: CGImageRef = CGImageCreateWithMask(makedImage.CGImage, imageMaskOne)!
//Finished
let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 350, height: 350))
imageView.image = UIImage(CGImage: masked)
self.addSubview(imageView)
If you just need to create a crop at a specific coordinates there is an easier way CGImageCreateWithImageInRect
func CGImageCreateWithImageInRect(_ image: CGImage?, _ rect: CGRect) -> CGImage?
Here the documentation.
Related
I have two images, which both have alpha channel. I want to comine them together. It do works for UIImageView, but I want to do it by using cgimage, which without creat a UIImageView.
I tried cgimage like this is not working:
func combine3(_ bg: UIImage, cover: UIImage) -> UIImage?{
let size = CGSize(width: self.view.frame.width, height: self.view.frame.height)
UIGraphicsBeginImageContext(size)
let maskRef = cover.cgImage!
let mask = CGImage.init(maskWidth: maskRef.width, height: maskRef.height, bitsPerComponent: maskRef.bitsPerComponent, bitsPerPixel: maskRef.bitsPerPixel, bytesPerRow: maskRef.bytesPerRow, provider: maskRef.dataProvider!, decode: nil, shouldInterpolate: false)
let masked = bg.cgImage?.masking(mask!)
let outPutImage = UIImage(cgImage: masked!)
UIGraphicsEndImageContext()
return outPutImage
}
but for UIImageView, it works pretty good:
let bg = creatBGImageFinal()!
bgIV.image = bg
let cover = createCoverImageFinal(progress: 0)!
let layer = CALayer()
layer.contents = cover.cgImage
layer.frame = CGRect(x: 0, y: 0, width: size.width, height: size.height)
maskIV.layer.mask = layer
bg:
cover,which is a picture with an white circle in the middle, the others is Transparent:
result:
First, reverse the mask:
The rule for cgImage masking is Dst = 1 - Src.
Then draw the masked image onto image context with opacity:
func combine3(_ bg: UIImage, cover: UIImage, size: CGSize) -> UIImage? {
UIGraphicsBeginImageContextWithOptions(size, true, 1)
defer {
UIGraphicsEndImageContext()
}
let context = UIGraphicsGetCurrentContext()!
let maskRef = cover.cgImage!
let mask = CGImage.init(maskWidth: maskRef.width, height: maskRef.height, bitsPerComponent: maskRef.bitsPerComponent, bitsPerPixel: maskRef.bitsPerPixel, bytesPerRow: maskRef.bytesPerRow, provider: maskRef.dataProvider!, decode: nil, shouldInterpolate: false)!
let masked = bg.cgImage!.masking(mask)!
// adjust for lower-left-origin CG coordinates
context.translateBy(x: 0, y: size.height)
context.scaleBy(x: 1, y: -1)
context.draw(masked, in: CGRect(origin: .zero, size: size))
return UIGraphicsGetImageFromCurrentImageContext()
}
Result:
I know there are several other ways to do this; I don't want to import anything that I don't need to. If someone can help me with his code, that would be great.
Currently, it is only saving the original image without the watermark image.
extension UIImage {
class func imageWithWatermark(image1: UIImageView, image2: UIImageView) -> UIImage {
UIGraphicsBeginImageContextWithOptions(image1.bounds.size, false, 0.0)
image2.layer.renderInContext(UIGraphicsGetCurrentContext()!)
image1.layer.renderInContext(UIGraphicsGetCurrentContext()!)
let img = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return img
}
}
func addWatermark() {
let newImage = UIImage.imageWithWatermark(imageView, image2: watermarkImageView)
UIImageWriteToSavedPhotosAlbum(newImage, nil, nil, nil)
}
EDIT: I've got the watermark appearing on the saved images.
I had to switch the order of the layers:
image1.layer.renderInContext(UIGraphicsGetCurrentContext()!)
image2.layer.renderInContext(UIGraphicsGetCurrentContext()!)
HOWEVER, it is not appearing in the correct place.It seems to always appear in the center of the image.
If you grab the UIImageViews' images you could use the following concept:
if let img = UIImage(named: "image.png"), img2 = UIImage(named: "watermark.png") {
let rect = CGRect(x: 0, y: 0, width: img.size.width, height: img.size.height)
UIGraphicsBeginImageContextWithOptions(img.size, true, 0)
let context = UIGraphicsGetCurrentContext()
CGContextSetFillColorWithColor(context, UIColor.whiteColor().CGColor)
CGContextFillRect(context, rect)
img.drawInRect(rect, blendMode: .Normal, alpha: 1)
img2.drawInRect(CGRectMake(x,y,width,height), blendMode: .Normal, alpha: 1)
let result = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
UIImageWriteToSavedPhotosAlbum(result, nil, nil, nil)
}
SWIFT 4
Use this
let backgroundImage = imageData!
let watermarkImage = #imageLiteral(resourceName: "jodi_url_icon")
let size = backgroundImage.size
let scale = backgroundImage.scale
UIGraphicsBeginImageContextWithOptions(size, false, scale)
backgroundImage.draw(in: CGRect(x: 0.0, y: 0.0, width: size.width, height: size.height))
watermarkImage.draw(in: CGRect(x: 10, y: 10, width: size.width, height: size.height - 40))
let result = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
Use result to UIImageView, tested.
Trying to mask an image with my custom mask. I think I follow the ideas correctly, but for some reason, image isn't get masked. Instead, masked image, created after masking, contains original cropped image as the mask wasn't applied.
Here's the Swift playground code which one can use in order to test my code (image and mask are attached, just drop them to the resources folder):
import UIKit
extension UIImage {
static func resizeImage(image: UIImage, width: CGFloat) -> UIImage {
let scale = width / image.size.width
let newHeight = round(image.size.height * scale)
UIGraphicsBeginImageContextWithOptions(CGSize(width:width, height:newHeight), false, image.scale)
image.draw(in: CGRect(origin: CGPoint(x:0, y:0), size: CGSize(width: width, height: newHeight)))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
static func resizeImage(image: UIImage, height: CGFloat) -> UIImage {
let scale = height / image.size.height
let newWidth = round(image.size.width * scale)
UIGraphicsBeginImageContextWithOptions(CGSize(width:newWidth, height:height), false, image.scale)
image.draw(in: CGRect(origin: CGPoint(x:0, y:0), size: CGSize(width: newWidth, height: height)))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
}
let image = UIImage(named: "image.jpg")!
var mask = UIImage(named: "mask.jpg")!
let k1 = image.size.width / image.size.height
let k2 = mask.size.width / mask.size.height
if k1 >= k2
{
mask = UIImage.resizeImage(image: mask, height: image.size.height)
}
else
{
mask = UIImage.resizeImage(image: mask, width: image.size.width)
}
image
mask
let center = CGPoint(x: image.size.width/2, y: image.size.height/2)
let croppingRect = CGRect(x: abs(image.size.width-mask.size.width)/2*image.scale,
y: abs(image.size.height-mask.size.height)/2*image.scale,
width: mask.size.width*image.scale,
height: mask.size.height*image.scale).integral
let maskReference = mask.cgImage!
let imageReference = image.cgImage!.cropping(to: croppingRect)!
let imageMask = CGImage(maskWidth: maskReference.width,
height: maskReference.height,
bitsPerComponent: maskReference.bitsPerComponent,
bitsPerPixel: maskReference.bitsPerPixel,
bytesPerRow: maskReference.bytesPerRow,
provider: maskReference.dataProvider!, decode: nil, shouldInterpolate: true)
imageMask?.colorSpace
imageMask?.alphaInfo
let maskedReference = imageReference.masking(imageMask!)
let maskedImage = UIImage(cgImage:maskedReference!, scale: image.scale, orientation: image.imageOrientation)
Swift 4+
let icon = UIImageView(image: YOURIMAGE)
icon.frame = CGRect(x:100, y: 100, width: 100, height: 100)
icon.layer.masksToBounds = true
let maskView = UIImageView()
maskView.image = YOURMASKIMAGE
maskView.frame = icon.bounds
icon.mask = maskView
icon.contentMode = .scaleToFill
icon.clipsToBounds = true
view.addSubview(icon)
We can now create universal vector images in Xcode by adding them into image assets folder and then changing the scale factors to single vector. I would like to know how to do this programmatically. I've tried the following but no luck :(
func resizeImage(image: UIImage, newSize: CGSize) -> (UIImage) {
let newRect = CGRectIntegral(CGRectMake(0,0, newSize.width, newSize.height))
let imageRef = image.CGImage
let scaleFactor = UIScreen.mainScreen().scale
UIGraphicsBeginImageContextWithOptions(newSize, false, scaleFactor)
// UIGraphicsBeginImageContextWithOptions(newSize, false, 0.5)
let context = UIGraphicsGetCurrentContext()
// Set the quality level to use when rescaling
CGContextSetInterpolationQuality(context, CGInterpolationQuality.High)
let flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, newSize.height)
CGContextConcatCTM(context, flipVertical)
// Draw into the context; this scales the image
CGContextDrawImage(context, newRect, imageRef)
let newImageRef = CGBitmapContextCreateImage(context)! as CGImage
let newImage = UIImage(CGImage: newImageRef)
// Get the resized image from the context and a UIImage
UIGraphicsEndImageContext()
return newImage
}
This should do it. Yea...Apple kind of gears this towards setting it in storyboard by ticking the preserve vector data. I'm not sure how to preserve vector data programmatically.
public class var add: UIImage {
let path = bundle.url(forResource: "plusReal", withExtension: "pdf")
return drawPDFFromURL(url: path!)!
}
class func drawPDFFromURL(url: URL) -> UIImage? {
guard let document = CGPDFDocument(url as CFURL),
let page = document.page(at: 1) else {return nil }
let pageRect = page.getBoxRect(.mediaBox)
let renderer = UIGraphicsImageRenderer(size: pageRect.size)
let img = renderer.image { ctx in
UIColor.white.set()
ctx.fill(pageRect)
ctx.cgContext.translateBy(x: 0.0, y: pageRect.size.height)
ctx.cgContext.scaleBy(x: 1.0, y: -1.0)
ctx.cgContext.drawPDFPage(page)
}
return img
}
Why the image is rotated , by calling CGContextDrawImage.Thanks for your help.
// Initialization code
UIImage *img = [UIImage imageNamed:#"logo.png"];
UIImagePNGRepresentation(img);
_image_ref = img.CGImage;
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect img_rect = CGRectMake(20, 40, 100, 150);
CGContextDrawImage(context, img_rect, _image_ref);
core graphics's coordinated system not like UIKit, you need to calculate the right coordinate.
http://blog.ddg.com/?p=10
Following this explanation. I created solution which allow to draw multiple images with custom rects in one context.
func foo() -> UIImage? {
let image = UIImage(named: "back.png")!
let contextSize = CGSize(width: 500, height: 500)
UIGraphicsBeginImageContextWithOptions(contextSize, true, image.scale)
guard let ctx = UIGraphicsGetCurrentContext() else { return nil }
guard let cgImage = image.cgImage else { return nil}
//Start code which can by copy/paste
let imageRect = CGRect(origin: CGPoint(x: 200.0, y: 200.0), size: image.size) //custom rect
let ty = imageRect.origin.y + imageRect.size.height //calculate translation Y
let imageRectWithoutOriginY = CGRect(origin: CGPoint(x: imageRect.origin.x, y: 0), size: imageRect.size)
ctx.translateBy(x: 0.0, y: ty) //prepare context for custom rect
ctx.scaleBy(x: 1.0, y: -1.0)
ctx.draw(cgImage, in: imageRectWithoutOriginY) //draw image
ctx.translateBy(x: 0.0, y:-ty) //restore default context setup (so you can select new area to place another image)
ctx.scaleBy(x: 1.0, y: -1.0)
//End code which can by copy/paste
let result = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return result
}
Example with to images:
I know that it can be refactored. I duplicated code for more clarity.