I have a view that has a UIImage and a DrawView as subviews. The draw view responds to touches and creates a UIBezierPath for drawing on the image. When the user accepts their change I need to merge the underlying UIImage and any UIBezierPath's created into a single UIImage.
Make that UIBazierPath a public property of your DrawView, and keep updating it when user is drawing from within DrawView. When user hits the Accept button, use following code to simply Create a UIImageContext and draw both, the sourceImage and bezierPath over the context. Finally take whatever is drawn on the context in a resultImage.
UIBezierPath *path = drawView.Path // Your Bezier Path in DrawView
UIImage *sourceImage = sourceImageView.image; // Your Source Image from ImageView.
UIImage *resultImage = nil;
UIGraphicsBeginImageContext(sourceImage.size);
[sourceImage drawInRect:(CGRect){CGPointZero, sourceImage.size}];
[path stroke]; //Fill or Stroke path as you need.
[path fill];
resultImage = UIGraphicsGetImageFromCurrentImageContext(); //taking the merged result from context, in a new Image. This is your required image.
UIGraphicsEndImageContext();
//Use resultImage as you want.
Related
I want to show an image in NSview or in the NSImageView. In my header file I have
#interface FVView : NSView
{
NSImageView *imageView;
}
#end
here is what I been trying to do in my implementation file:
- (void)drawRect:(NSRect)dirtyRect
{
[super drawRect:dirtyRect];
(Here I get an image called fitsImage........ then I do)
//Here I make the image
CGImageRef cgImage = CGImageRetain([fitsImage CGImageScaledToSize:maxSize]);
NSImage *imageR = [self imageFromCGImageRef:cgImage];
[imageR lockFocus];
//Here I have the view context
CGContextRef ctx = (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
//Here I set the via dimensions
CGRect renderRect = CGRectMake(0., 0., maxSize.width, maxSize.height);
[self.layer renderInContext:ctx];
[imageR unlockFocus];
CGContextDrawImage(ctx, renderRect, cgImage);
CGImageRelease(cgImage);
}
I don't get anything in the NSview window when I run the script. No errors at all I just can't see what I'm doing wrong. My Xcode version in 5.1.1
I'm trying to learn how to manipulate CGImageRef and view it in a window or nsview.
Thank you.
I'm not quite sure what exactly your setup is. Drawing an image in a custom view is a separate thing from using an NSImageView. Also, a custom view that may (or may not) be layer-backed is different from a layer-hosting view.
You have a lot of the right elements, but they're all mixed up together. In no case do you have to lock focus on an NSImage. That's for drawing into an NSImage. Also, a custom view that subclasses from NSView doesn't have to call super in its -drawRect:. NSView doesn't draw anything.
To draw an image in a custom view, try:
- (void) drawRect:(NSRect)dirtyRect
{
CGImageRef cgImage = /* ... */;
NSSize maxSize = /* ... */;
CGContextRef ctx = (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
CGRect renderRect = CGRectMake(0., 0., maxSize.width, maxSize.height);
CGContextDrawImage(ctx, renderRect, cgImage);
CGImageRelease(cgImage);
}
If you have an NSImageView, then you don't need a custom view or any drawing method or code. Just do the following at the point where you obtain the image or the information necessary to generate it:
NSImageView* imageView = /* ... */; // Often an outlet to a view in a NIB rather than a local variable.
CGImageRef cgImage = /* ... */;
NSImage* image = [[NSImage alloc] initWithCGImage:cgImage size:/* ... */];
imageView.image = image;
CGImageRelease(cgImage);
If you're working with a layer-hosting view, you just need to set the CGImage as the layer's content. Again, you do this whenever you obtain the image or the information necessary to generate it. It's not in -drawRect:.
CALayer* layer = /* ... */; // Perhaps someView.layer
CGImageRef cgImage = /* ... */;
layer.contents = (__bridge id)cgImage;
CGImageRelease(cgImage);
I tried rotate image and view, only view or only image, but I have not got view that I need. I want just image with faces on the top of the screen, I can rotate a window, but I use my code not in AppDelegate and also I not want to rotate other elements, my code here, it rotate all view .
-(void)markFaces:(UIImageView *)facePicture
{
// draw a CI image with the previously loaded face detection picture
CIImage* image = [CIImage imageWithCGImage:facePicture.image.CGImage];
// create a face detector - since speed is not an issue we'll use a high accuracy
// detector
CIDetector* detector = [CIDetector detectorOfType:CIDetectorTypeFace
context:nil options:[NSDictionary dictionaryWithObject:CIDetectorAccuracyHigh forKey:CIDetectorAccuracy]];
// create an array containing all the detected faces from the detector
NSArray* features = [detector featuresInImage:image];
// we'll iterate through every detected face. CIFaceFeature provides us
// with the width for the entire face, and the coordinates of each eye
// and the mouth if detected. Also provided are BOOL's for the eye's and
// mouth so we can check if they already exist.
for(CIFaceFeature* faceFeature in features)
{
// get the width of the face
CGFloat faceWidth = faceFeature.bounds.size.width;
// create a UIView using the bounds of the face
UIView* faceView = [[UIView alloc] initWithFrame:faceFeature.bounds];
// add a border around the newly created UIView
faceView.layer.borderWidth = 1;
faceView.layer.borderColor = [[UIColor redColor] CGColor];
faceView.backgroundColor = [UIColor blackColor];
// add the new view to create a box around the face
//[faceView setTransform:CGAffineTransformMakeScale(-1, -1)];
[self.view addSubview:faceView];
[self.view setTransform:CGAffineTransformMakeScale(-1, -1)]; // !!!!
}
-(void)faceDetector
{
// Load the picture for face detection
UIImageView* image = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"test1.jpeg"]];
// Draw the face detection image
[self.view addSubview:image];
// Execute the method used to markFaces in background
[self performSelectorInBackground:#selector(markFaces:) withObject:image];
// flip image on y-axis to match coordinate system used by core image
[image setTransform:CGAffineTransformMakeScale(1, -1)];//!!
}
I have a custom subclass of NSView that implements drag/drop for copying the image in the view to another application. The relevant code in my class looks like this:
#pragma mark -
#pragma mark Dragging Support
- (NSImage *)imageWithSubviews
{
NSSize imgSize = self.bounds.size;
NSBitmapImageRep *bir = [[NSBitmapImageRep alloc] initWithFocusedViewRect:[self frame]];
[self cacheDisplayInRect:[self frame] toBitmapImageRep:bir];
NSImage* image = [[NSImage alloc]initWithSize:imgSize];
[image addRepresentation:bir];
return image;
}
- (void)mouseDown:(NSEvent *)theEvent
{
NSSize dragOffset = NSMakeSize(0.0, 0.0); // not used in the method below, but required.
NSPasteboard *pboard;
NSImage *image = [self imageWithSubviews];
pboard = [NSPasteboard pasteboardWithName:NSDragPboard];
[pboard declareTypes:[NSArray arrayWithObject:NSTIFFPboardType]
owner:self];
[pboard setData:[image TIFFRepresentation]
forType:NSTIFFPboardType];
[self dragImage:image
at:self.bounds.origin
offset:dragOffset
event:theEvent
pasteboard:pboard
source:self
slideBack:YES];
return;
}
#pragma mark -
#pragma mark NSDraggingSource Protocol
- (NSDragOperation)draggingSession:(NSDraggingSession *)session sourceOperationMaskForDraggingContext:(NSDraggingContext)context
{
return NSDragOperationCopy;
}
- (BOOL)ignoreModifierKeysForDraggingSession:(NSDraggingSession *)session
{
return YES;
}
This works as expected until I resize the main window. The main window only increases size/width in the same increments to maintain the proper ratio in this view. The view properly displays its content on the screen when the window is resized.
The problem comes when I resize the window more than about + 25%. While it still displays as expected, the image that is dragged off of it (into Pages, for example) is corrupt. It appears to have a portion of this image repeated on top of itself.
Here is what it looks like normally:
And here is what it looks like when dragged to Pages after resizing the main window to make it large (downsized to show here -- imagine it at 2-3x the size of the first image):
Note that I highlighted the corrupt area with a dotted rectangle.
A few more notes:
I have my bounds set like NSMakeRect(-200,-200,400,400) because it makes the symmetrical drawing a bit easier. When the window resizes, I recalculate the bounds to keep 0,0 in the center of the NSView. The NSView always is square.
Finally, the Apple docs state the following for the bitmapImageRep parameter in cacheDisplayInRect:toBitmapImageRep: should
An NSBitmapImageRep object. For pixel-format compatibility, bitmapImageRep should have been obtained from bitmapImageRepForCachingDisplayInRect:.
I've tried using bitmapImageRepForCachingDisplayInRect:, but then all I see is the lower-left quadrant of the pyramid in the upper-right quadrant of the image. That makes me think that I need to add an offset for the capture of the bitmapImageRep, but I've been unable to determine how to do that.
Here's what the code for imageWithSubviews looks like when I try that:
- (NSImage *)imageWithSubviews
{
NSSize imgSize = self.bounds.size;
NSBitmapImageRep *bir = [self bitmapImageRepForCachingDisplayInRect:[self bounds]];
[self cacheDisplayInRect:[self bounds] toBitmapImageRep:bir];
NSImage* image = [[NSImage alloc]initWithSize:imgSize];
[image addRepresentation:bir];
return image;
}
And this is how the resulting image appears:
That is a view of the lower left quadrant being drawn in the upper-right corner.
What is causing the corruption when I drag from the NSView after enlarging the window? How to I fix that and/or change my implementation of the methods that I listed above to avoid the problem?
More info:
When I change the imageWithSubviews method to:
- (NSImage *)imageWithSubviews
{
NSSize imgSize = self.bounds.size;
NSBitmapImageRep *bir = [[NSBitmapImageRep alloc] initWithFocusedViewRect:[self frame]];
[self cacheDisplayInRect:[self bounds] toBitmapImageRep:bir];
NSImage* image = [[NSImage alloc]initWithSize:imgSize];
[image addRepresentation:bir];
return image;
}
I get a corrupted image without scaling, where the bottom-left quadrant of the image is drawn again on top of the top-right quadrant, like this:
What in the world am I doing wrong?
Solution:
While it does not address the core problem of drawing with NSBitmapImageRep, the following -imageWithSubviews prevents the corruption and outputs the correct image:
- (NSImage *)imageWithSubviews
{
NSData *pdfData = [self dataWithPDFInsideRect:[self bounds]];
NSImage* image = [[NSImage alloc] initWithData:pdfData];
return image;
}
Based on some debugging above, we determined the problem was in -imageWithSubviews.
Instead of generating image data for the view using -cacheDisplayInRect:toBitmapImageRep:, changing it to -dataWithPDFInRect: fixed the issue.
How to shadow documentView in NSScrollView?
The effect look likes iBook Author:
You need to inset the content in your document view to allow space for the shadow to be displayed, then layer back the view and set a shadow on it. Example:
view.wantsLayer = YES;
NSShadow *shadow = [NSShadow new];
shadow.shadowColor = [NSColor blackColor]
shadow.shadowBlurRadius = 4.f;
shadow.shadowOffset = NSMakeSize(0.f, -5.f);
view.shadow = shadow;
The NSScrollView contentView is an NSView subclass, which has a shadow field, if you create a shadow object and assign it to this field, the view will automatically show a drop shadow when drawn
NSShadow* shadow = [[NSShadow alloc] init];
shadow.shadowBlurRadius = 2; //set how many pixels the shadow has
shadow.shadowOffset = NSMakeSize(2, -2); //the distance from the view the shadow is dropped
shadow.shadowColor = [NSColor blackColor];
self.scrollView.contentView.shadow = shadow;
This works because all views when are drawn on drawRect use this shadow property by using [shadow set].
doing [shadow set] during a draw operation makes whatever is drawn after that to be replicated underneath
I'm new to entering posts on stack overflow but I had the same issue and have solved it so I thought after searching the net for hours to find a solution it would be nice to answer it.
My solution is to create a subclass for NSClipView with the following code for drawRect...
- (void)drawRect:(NSRect)dirtyRect
{
[super drawRect:dirtyRect];
NSRect childRect = [[self documentView] frame];
[NSGraphicsContext saveGraphicsState];
// Create the shadow below and to the right of the shape.
NSShadow* theShadow = [[NSShadow alloc] init];
[theShadow setShadowOffset:NSMakeSize(4.0, -4.0)];
[theShadow setShadowBlurRadius:3.0];
// Use a partially transparent color for shapes that overlap.
[theShadow setShadowColor:[[NSColor grayColor]
colorWithAlphaComponent:0.95f]];
[theShadow set];
[[self backgroundColor] setFill];
NSRectFill(childRect);
// Draw your custom content here. Anything you draw
// automatically has the shadow effect applied to it.
[NSGraphicsContext restoreGraphicsState];
}
You then need to create an instance of the subclass and set it with the setContentView selector.
You also need to repaint the clip view every time the content view size changes. If you have your content view set up to change in terms of canvas size when the user wants then unless you repaint the clip view some nasty shadow marks will left behind.
You don't need to mess about with clips as others have suggested.
Hope it helps!
I want to set a custom mouse cursor for my app and would like to programmatically change the default cursor's color to a custom color by replacing the white border with the custom color. The problem is that I don't even know where to start to programmatically edit images in Cocoa, so any help is appreciated!
You can get the default cursor with -[NSCursor arrowCursor]. Once you have a cursor, you can get its image with -[NSCursor image]. You shouldn't modify another object's image, so you should copy that image. Then you should edit the image, and create a new cursor with -[NSCursor initWithImage:hotSpot:]. Your code should look something like this:
- (NSImage *)customArrowCursorImage {
NSImage *image = [[[NSCursor arrowCursor] image] copy];
[image lockFocus];
/// Do custom drawing
[image unlockFocus];
}
- (NSCursor *)customArrowCursor {
NSImage *image = [self customArrowCursorImage];
NSPoint hotSpot = [[NSCursor arrowCursor] hotSpot];
return [[[NSCursor alloc] initWithImage:image hotSpot:hotSpot] autorelease];
}
You should be able to replace the white color of the image with a custom color by using a core image filter. But if you just want to get started, you can use NSReadPixel() and NSRectFill to color one pixel at a time. Drawing one pixel a a time like that with with NSReadPixel and NSRectFill will be exceptionally slow, so you should only do that to get a feel for how all of this works.
My final code. This takes the standard IBeam cursor (that one when you hover over a textview) and stores the colored cursor in the coloredIBeamCursor pointer.
- (void)setPointerColor:(NSColor *)newColor {
// create the new cursor image
[[NSGraphicsContext currentContext] CIContext];
// create the layer with the same color as the text
CIFilter *backgroundGenerator=[CIFilter filterWithName:#"CIConstantColorGenerator"];
CIColor *color=[[[CIColor alloc] initWithColor:newColor] autorelease];
[backgroundGenerator setValue:color forKey:#"inputColor"];
CIImage *backgroundImage=[backgroundGenerator valueForKey:#"outputImage"];
// create the cursor image
CIImage *cursor=[CIImage imageWithData:[[[NSCursor IBeamCursor] image] TIFFRepresentation]];
CIFilter *filter=[CIFilter filterWithName:#"CIColorInvert"];
[filter setValue:cursor forKey:#"inputImage"];
CIImage *outputImage=[filter valueForKey:#"outputImage"];
// apply a multiply filter
filter=[CIFilter filterWithName:#"CIMultiplyCompositing"];
[filter setValue:backgroundImage forKey:#"inputImage"];
[filter setValue:outputImage forKey:#"inputBackgroundImage"];
outputImage=[filter valueForKey:#"outputImage"];
// get the NSImage from the CIImage
NSCIImageRep *rep=[NSCIImageRep imageRepWithCIImage:outputImage];
NSImage *newImage=[[[NSImage alloc] initWithSize:[outputImage extent].size] autorelease];
[newImage addRepresentation:rep];
// remove the old cursor (if any)
if (coloredIBeamCursor!=nil) {
[self removeCursorRect:[self visibleRect] cursor:coloredIBeamCursor];
[coloredIBeamCursor release];
}
// set the new cursor
NSCursor *coloredIBeamCursor=[[NSCursor alloc] initWithImage:newImage hotSpot:[[NSCursor IBeamCursor] hotSpot]];
[self resetCursorRects];
}