CGImage Masking with UIImage pngData()
I'm trying to mask an image in swift. Here's my code:
(Normally, originalImg is an image that is loaded from UIImagePickerController and then cropped by UIGraphicsGetImageFromCurrentImageContext(), andmakedImage is an image that is drawn by the user, created by UIGraphicsGetImageFromCurrentImageContext())
func imageMasking(_ originalImg: UIImage, maskImage: UIImage) -> UIImage {
let cgMaskImage = maskImage.cgImage!
let mask = CGImage(maskWidth: cgMaskImage.width, height: cgMaskImage.height, bitsPerComponent: cgMaskImage.bitsPerComponent, bitsPerPixel: cgMaskImage.bitsPerPixel, bytesPerRow: cgMaskImage.bytesPerRow, provider: cgMaskImage.dataProvider!, decode: nil, shouldInterpolate: true)!
return UIImage(cgImage: originalImg.cgImage!.masking(mask)!)
}
When I display the resulted UIImage to UIImageView, it works well. However, when I try to get the pngData() of the resulted UIImage, the image data is identical to originalImg.
I also tried to export the pngData() of the resulted image from Xcode, but it is still the same as originalImg.
Image: https://imgur.com/tEVBWUQ (then click the 'Export...' button and save as png image)
How can I really mask an image?
ios swift image mask masking
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
add a comment |
I'm trying to mask an image in swift. Here's my code:
(Normally, originalImg is an image that is loaded from UIImagePickerController and then cropped by UIGraphicsGetImageFromCurrentImageContext(), andmakedImage is an image that is drawn by the user, created by UIGraphicsGetImageFromCurrentImageContext())
func imageMasking(_ originalImg: UIImage, maskImage: UIImage) -> UIImage {
let cgMaskImage = maskImage.cgImage!
let mask = CGImage(maskWidth: cgMaskImage.width, height: cgMaskImage.height, bitsPerComponent: cgMaskImage.bitsPerComponent, bitsPerPixel: cgMaskImage.bitsPerPixel, bytesPerRow: cgMaskImage.bytesPerRow, provider: cgMaskImage.dataProvider!, decode: nil, shouldInterpolate: true)!
return UIImage(cgImage: originalImg.cgImage!.masking(mask)!)
}
When I display the resulted UIImage to UIImageView, it works well. However, when I try to get the pngData() of the resulted UIImage, the image data is identical to originalImg.
I also tried to export the pngData() of the resulted image from Xcode, but it is still the same as originalImg.
Image: https://imgur.com/tEVBWUQ (then click the 'Export...' button and save as png image)
How can I really mask an image?
ios swift image mask masking
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
I think you can render the result of imageMasking into bitmap context and get result image from the context.
– Andrew Romanov
Dec 29 '18 at 9:15
add a comment |
I'm trying to mask an image in swift. Here's my code:
(Normally, originalImg is an image that is loaded from UIImagePickerController and then cropped by UIGraphicsGetImageFromCurrentImageContext(), andmakedImage is an image that is drawn by the user, created by UIGraphicsGetImageFromCurrentImageContext())
func imageMasking(_ originalImg: UIImage, maskImage: UIImage) -> UIImage {
let cgMaskImage = maskImage.cgImage!
let mask = CGImage(maskWidth: cgMaskImage.width, height: cgMaskImage.height, bitsPerComponent: cgMaskImage.bitsPerComponent, bitsPerPixel: cgMaskImage.bitsPerPixel, bytesPerRow: cgMaskImage.bytesPerRow, provider: cgMaskImage.dataProvider!, decode: nil, shouldInterpolate: true)!
return UIImage(cgImage: originalImg.cgImage!.masking(mask)!)
}
When I display the resulted UIImage to UIImageView, it works well. However, when I try to get the pngData() of the resulted UIImage, the image data is identical to originalImg.
I also tried to export the pngData() of the resulted image from Xcode, but it is still the same as originalImg.
Image: https://imgur.com/tEVBWUQ (then click the 'Export...' button and save as png image)
How can I really mask an image?
ios swift image mask masking
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
I'm trying to mask an image in swift. Here's my code:
(Normally, originalImg is an image that is loaded from UIImagePickerController and then cropped by UIGraphicsGetImageFromCurrentImageContext(), andmakedImage is an image that is drawn by the user, created by UIGraphicsGetImageFromCurrentImageContext())
func imageMasking(_ originalImg: UIImage, maskImage: UIImage) -> UIImage {
let cgMaskImage = maskImage.cgImage!
let mask = CGImage(maskWidth: cgMaskImage.width, height: cgMaskImage.height, bitsPerComponent: cgMaskImage.bitsPerComponent, bitsPerPixel: cgMaskImage.bitsPerPixel, bytesPerRow: cgMaskImage.bytesPerRow, provider: cgMaskImage.dataProvider!, decode: nil, shouldInterpolate: true)!
return UIImage(cgImage: originalImg.cgImage!.masking(mask)!)
}
When I display the resulted UIImage to UIImageView, it works well. However, when I try to get the pngData() of the resulted UIImage, the image data is identical to originalImg.
I also tried to export the pngData() of the resulted image from Xcode, but it is still the same as originalImg.
Image: https://imgur.com/tEVBWUQ (then click the 'Export...' button and save as png image)
How can I really mask an image?
ios swift image mask masking
ios swift image mask masking
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
asked Dec 29 '18 at 6:03
KeroppiMomoKeroppiMomo
434
434
I think you can render the result of imageMasking into bitmap context and get result image from the context.
– Andrew Romanov
Dec 29 '18 at 9:15
add a comment |
I think you can render the result of imageMasking into bitmap context and get result image from the context.
– Andrew Romanov
Dec 29 '18 at 9:15
I think you can render the result of imageMasking into bitmap context and get result image from the context.
– Andrew Romanov
Dec 29 '18 at 9:15
I think you can render the result of imageMasking into bitmap context and get result image from the context.
– Andrew Romanov
Dec 29 '18 at 9:15
add a comment |
1 Answer
1
active
oldest
votes
Just draw a masked image into image context:
func drawImage(_ image: UIImage) -> UIImage?
{
guard let coreImage = image.cgImage else {
return nil;
}
UIGraphicsBeginImageContext(CGSize(width: coreImage.width, height: coreImage.height))
image.draw(in: CGRect(x: 0.0, y: 0.0, width: coreImage.width, height: coreImage.height))
let resultImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return resultImage;
}
Also you can draw image into bitmap context or image renderer and get result image.
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
It works! Can you explain why you need to draw it to image context before callingpngData()? Also, whyUIImagecan show the masked image before drawing to image context? Thx!
– KeroppiMomo
Dec 29 '18 at 9:36
iPhone is a small device with small size of memory, but with strong GPU. Many components and methods of the SDK is lazy, for example if you create UIImage you will not load binary data into memory, data will be loaded late. Methods of CGImage, that can produce other images work in lazy way. You do not copy data when create CGImage via other CGImage. (In same way work CIImage, UIImage, CGImage, CGBitmapContextCreateImage, and many other components of the SDK)
– Andrew Romanov
Dec 29 '18 at 10:31
Thx! Your explanation is very clear.
– KeroppiMomo
Dec 29 '18 at 10:33
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53967126%2fcgimage-masking-with-uiimage-pngdata%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Just draw a masked image into image context:
func drawImage(_ image: UIImage) -> UIImage?
{
guard let coreImage = image.cgImage else {
return nil;
}
UIGraphicsBeginImageContext(CGSize(width: coreImage.width, height: coreImage.height))
image.draw(in: CGRect(x: 0.0, y: 0.0, width: coreImage.width, height: coreImage.height))
let resultImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return resultImage;
}
Also you can draw image into bitmap context or image renderer and get result image.
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
It works! Can you explain why you need to draw it to image context before callingpngData()? Also, whyUIImagecan show the masked image before drawing to image context? Thx!
– KeroppiMomo
Dec 29 '18 at 9:36
iPhone is a small device with small size of memory, but with strong GPU. Many components and methods of the SDK is lazy, for example if you create UIImage you will not load binary data into memory, data will be loaded late. Methods of CGImage, that can produce other images work in lazy way. You do not copy data when create CGImage via other CGImage. (In same way work CIImage, UIImage, CGImage, CGBitmapContextCreateImage, and many other components of the SDK)
– Andrew Romanov
Dec 29 '18 at 10:31
Thx! Your explanation is very clear.
– KeroppiMomo
Dec 29 '18 at 10:33
add a comment |
Just draw a masked image into image context:
func drawImage(_ image: UIImage) -> UIImage?
{
guard let coreImage = image.cgImage else {
return nil;
}
UIGraphicsBeginImageContext(CGSize(width: coreImage.width, height: coreImage.height))
image.draw(in: CGRect(x: 0.0, y: 0.0, width: coreImage.width, height: coreImage.height))
let resultImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return resultImage;
}
Also you can draw image into bitmap context or image renderer and get result image.
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
It works! Can you explain why you need to draw it to image context before callingpngData()? Also, whyUIImagecan show the masked image before drawing to image context? Thx!
– KeroppiMomo
Dec 29 '18 at 9:36
iPhone is a small device with small size of memory, but with strong GPU. Many components and methods of the SDK is lazy, for example if you create UIImage you will not load binary data into memory, data will be loaded late. Methods of CGImage, that can produce other images work in lazy way. You do not copy data when create CGImage via other CGImage. (In same way work CIImage, UIImage, CGImage, CGBitmapContextCreateImage, and many other components of the SDK)
– Andrew Romanov
Dec 29 '18 at 10:31
Thx! Your explanation is very clear.
– KeroppiMomo
Dec 29 '18 at 10:33
add a comment |
Just draw a masked image into image context:
func drawImage(_ image: UIImage) -> UIImage?
{
guard let coreImage = image.cgImage else {
return nil;
}
UIGraphicsBeginImageContext(CGSize(width: coreImage.width, height: coreImage.height))
image.draw(in: CGRect(x: 0.0, y: 0.0, width: coreImage.width, height: coreImage.height))
let resultImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return resultImage;
}
Also you can draw image into bitmap context or image renderer and get result image.
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
Just draw a masked image into image context:
func drawImage(_ image: UIImage) -> UIImage?
{
guard let coreImage = image.cgImage else {
return nil;
}
UIGraphicsBeginImageContext(CGSize(width: coreImage.width, height: coreImage.height))
image.draw(in: CGRect(x: 0.0, y: 0.0, width: coreImage.width, height: coreImage.height))
let resultImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return resultImage;
}
Also you can draw image into bitmap context or image renderer and get result image.
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
answered Dec 29 '18 at 9:30
Andrew RomanovAndrew Romanov
2,44521730
2,44521730
It works! Can you explain why you need to draw it to image context before callingpngData()? Also, whyUIImagecan show the masked image before drawing to image context? Thx!
– KeroppiMomo
Dec 29 '18 at 9:36
iPhone is a small device with small size of memory, but with strong GPU. Many components and methods of the SDK is lazy, for example if you create UIImage you will not load binary data into memory, data will be loaded late. Methods of CGImage, that can produce other images work in lazy way. You do not copy data when create CGImage via other CGImage. (In same way work CIImage, UIImage, CGImage, CGBitmapContextCreateImage, and many other components of the SDK)
– Andrew Romanov
Dec 29 '18 at 10:31
Thx! Your explanation is very clear.
– KeroppiMomo
Dec 29 '18 at 10:33
add a comment |
It works! Can you explain why you need to draw it to image context before callingpngData()? Also, whyUIImagecan show the masked image before drawing to image context? Thx!
– KeroppiMomo
Dec 29 '18 at 9:36
iPhone is a small device with small size of memory, but with strong GPU. Many components and methods of the SDK is lazy, for example if you create UIImage you will not load binary data into memory, data will be loaded late. Methods of CGImage, that can produce other images work in lazy way. You do not copy data when create CGImage via other CGImage. (In same way work CIImage, UIImage, CGImage, CGBitmapContextCreateImage, and many other components of the SDK)
– Andrew Romanov
Dec 29 '18 at 10:31
Thx! Your explanation is very clear.
– KeroppiMomo
Dec 29 '18 at 10:33
It works! Can you explain why you need to draw it to image context before calling
pngData()? Also, why UIImage can show the masked image before drawing to image context? Thx!– KeroppiMomo
Dec 29 '18 at 9:36
It works! Can you explain why you need to draw it to image context before calling
pngData()? Also, why UIImage can show the masked image before drawing to image context? Thx!– KeroppiMomo
Dec 29 '18 at 9:36
iPhone is a small device with small size of memory, but with strong GPU. Many components and methods of the SDK is lazy, for example if you create UIImage you will not load binary data into memory, data will be loaded late. Methods of CGImage, that can produce other images work in lazy way. You do not copy data when create CGImage via other CGImage. (In same way work CIImage, UIImage, CGImage, CGBitmapContextCreateImage, and many other components of the SDK)
– Andrew Romanov
Dec 29 '18 at 10:31
iPhone is a small device with small size of memory, but with strong GPU. Many components and methods of the SDK is lazy, for example if you create UIImage you will not load binary data into memory, data will be loaded late. Methods of CGImage, that can produce other images work in lazy way. You do not copy data when create CGImage via other CGImage. (In same way work CIImage, UIImage, CGImage, CGBitmapContextCreateImage, and many other components of the SDK)
– Andrew Romanov
Dec 29 '18 at 10:31
Thx! Your explanation is very clear.
– KeroppiMomo
Dec 29 '18 at 10:33
Thx! Your explanation is very clear.
– KeroppiMomo
Dec 29 '18 at 10:33
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53967126%2fcgimage-masking-with-uiimage-pngdata%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
I think you can render the result of imageMasking into bitmap context and get result image from the context.
– Andrew Romanov
Dec 29 '18 at 9:15