quartz-graphics

问题 I am displaying text using Quartz. Here is my code: CGContextRef myContext = UIGraphicsGetCurrentContext(); CGContextSelectFont(myContext, "Helvetica", 12, kCGEncodingMacRoman); CGContextSetCharacterSpacing(myContext, 8); CGContextSetTextDrawingMode(myContext, kCGTextFillStroke); CGContextSetRGBFillColor(myContext, 0, 0, 0, 1); CGContextSetRGBStrokeColor(myContext, 0, 0, 0, 1); CGContextSetTextMatrix(myContext,CGAffineTransformMake(1, 0, 0, -1, 0, 0)); CGContextShowTextAtPoint(myContext,

问题 I have been able to add shadows to many UI objects in my view, including rather nicely drop shadowing some custom drawing in a UIImageView. However the same code produces nothing when applied to a UITextView: [desc.layer setShadowColor:[[UIColor blackColor] CGColor]]; [desc.layer setShadowRadius:2.0f]; [desc.layer setShadowOffset:CGSizeMake(1, 1)]; [desc.layer setShadowOpacity:0.8f]; Is this something I'm missing? I was hoping to use quartz to add a border and a drop shadow. The border code

问题 How can I reproduce this shadowing? My problem, that if I use high alpha color or clearColor, there is no drop shadow, if I use low alpha color, I can't see the drop shadow under the plate. As the level of the volume is changing (colorful part) the shadow is moving also, so it is not pure Photoshop. 回答1: try something using thoses properies of your view. it might end up with something view.layer.shadowColor = [UIColor colorWithWhite:.5 alpha:1].CGColor; view.layer.shadowRadius = 4.0f; view

问题 I followed the tutorial on this page: http://iphone-3d-programming.labs.oreilly.com/ch01.html I got down to the part where it says, "Compile and build and you should now see a solid gray screen. Hurray!" However, when I ran the program, I just get a black screen. These are what the files look like: HelloArrowAppDelegate.h #import <UIKit/UIKit.h> #import "GLView.h" @interface HelloArrowAppDelegate : NSObject <UIApplicationDelegate> { UIWindow *m_window; GLView* m_view; } @end

问题 I am drawing a line animation, connecting 2 points with a line. This is my code: -(void) drawObject{ rootLayer = [CALayer layer]; rootLayer.frame = self.view.bounds; [self.view.layer addSublayer:rootLayer]; lineStartPath = CGPathCreateMutable(); CGPathMoveToPoint(lineStartPath, nil, 160, 50); CGPathAddLineToPoint(lineStartPath, nil, 160, 50); CGPathCloseSubpath(lineStartPath); lineEndPath = CGPathCreateMutable(); CGPathMoveToPoint(lineEndPath, nil, 160, 50); CGPathAddLineToPoint(lineEndPath,

问题 I am trying to trap keypresses using a CGEventTapCreate etc in Swift. I want to do this so that when my toddler is using a program the Mac, I can limit which keys do something. I appreciate that I need to enable assistive technology to get CGEventTap to work I am having trouble understanding what I need to do in Swift to get the final parameter in the call. Essentially, I do not understand part of the documentation at quartz event documentation Specifically the final parameter which is

问题 Just wondering if there is a way to receive a callback in Cocoa if Magic Mouse or Trackpad is being touched by the user? I looked into Quartz Events, but it seems I can only get callbacks if the mouse is moving or clicked etc. Note that I want to receive a callback even if my app is not active. It's a background utility app. Also, it can't use private frameworks as it's going to be a Mac App Store app. 回答1: You could use this code to trap the events: (create a new Cocoa application and put

问题 I'm developing an iPhone app with 3.1.3 SDK. I'm trying to draw a triangle with transparent fill an 1px black stroke with this code: CGContextMoveToPoint(ctx, position.X, position.Y - (size.height / 2)); CGContextAddLineToPoint(ctx, position.X - (size.width / 2), position.Y + (size.height / 2)); CGContextAddLineToPoint(ctx, position.X + (size.width / 2), position.Y + (size.height / 2)); CGContextFillPath(ctx); CGContextSetLineWidth(ctx, 1.0); CGContextStrokePath(ctx);

问题 I need to send mouse click events to an arbitrary process (not necessarily the front one) without bringing that process's window to the front. This code works for sending a mouse click and letting the window server send it to whatever process it decides has focus: #include <ApplicationServices/ApplicationServices.h> int main() { CGEventRef down, up; down = CGEventCreateMouseEvent( NULL, kCGEventLeftMouseDown, CGPointMake(16, 36), kCGMouseButtonLeft ); up = CGEventCreateMouseEvent( NULL,

问题 How effective is the CGContextSetInterpolationQuality method in Quartz? Does it affect the quality of the image? If so, to what extent? I can't see any difference between the interpolated and the non-interpolated image. 回答1: Although this is a bit of an old question, I have recently done some benchmarking about the effects of CGContextSetInterpolationQuality and thought that its outcomes might be of interest to someone else. In my benchmark test, I draw a set of 6 different 649x649 b&w bitmap