NSAffineTransform Examples

1. - (void) drawAnnotationElement:(unsigned) indx maxElement:(unsigned) max inRect:(NSRect) aRect atEdge:(DKOGridEdge) edge 
2. {
3. //<indx> is the ordinal item to draw, starting from 0. The actual drawn element factors in the offset and increment. <edge> specifies which edge(s) the annotation // should be drawn at. It will be left or right. For vertical annotation left == top, right == bottom. 
4.         
5.         if( edge == 0 )
6.                 return;         // nothing to do
7.         
8.         NSString*       str = [self annotationStringForElement:indx 
9. maxElement:max];
10. NSAttributedString* std = [[NSAttributedString alloc] initWithString:str attributes:[self textAttributes]]; 
11.         NSRect  bbox, ir;
12.         
13.         // get the bounding box for the string
15.         bbox.size = [std size];
16.         ir = [mGridRef borderRect];
17.         
18.         // swap the box width/height if rotated
19.         
20.         if([self isRotated])
21.         {
22.                 float temp = bbox.size.width;
23.                 bbox.size.width = bbox.size.height;
24.                 bbox.size.height = temp;
25.         }
26.         
27.         // position the box
28.         
29.         float textOffset = [mGridRef borderAllowance] + mOffset;
30.         
31.         float sd = [mGridRef spanLength];
32.         
33.         if([self orientationIsVertical])
34.         {
35.                 if( edge == kDKOLeftEdge )
36.                         bbox.origin.x = NSMinX( ir ) - bbox.size.width - 
37. textOffset;
38.                 else
39.                         bbox.origin.x = NSMaxX( ir ) + textOffset;
40.                 
41. bbox.origin.y = ( NSMinY( ir ) + ( sd * indx )) - (bbox.size.height * 0.5); 
42.                 
43.                 if([self placement] == kDKOPlaceAnnotationBetweenGrid )
44.                         bbox.origin.y += sd * 0.5;
45.                 
46.                 // don't draw if beyond end of interior
47.                 
48.                 if( bbox.origin.y > NSMaxY( ir ))
49.                         return;
50.         }
51.         else
52.         {
53.                 if( edge == kDKOLeftEdge )
54. bbox.origin.y = NSMinY( ir ) - bbox.size.height - ( textOffset * 0.7); 
55.                 else
56.                         bbox.origin.y = NSMaxY( ir ) + ( textOffset * 0.7 );
57.                 
58. bbox.origin.x = ( NSMinX( ir ) + ( sd * indx )) - (bbox.size.width * 0.5); 
59.                 
60.                 if([self placement] == kDKOPlaceAnnotationBetweenGrid )
61.                         bbox.origin.x += sd * 0.5;
62.                 
63.                 if( bbox.origin.x > NSMaxX( ir ))
64.                         return;
65.         }
66.         
67.         // draw the text in the box
68.         
69.         if( NSIntersectsRect( bbox, aRect ))
70.         {
71.                 NSPoint         origin = bbox.origin;
72.                 
73.                 [NSGraphicsContext saveGraphicsState];
74.                 
75.                 if([self isRotated])
76.                 {
77.                         NSAffineTransform* tfm = [NSAffineTransform transform];
78.                         
79.                         if([self orientationIsVertical])
80.                         {
81.                                 origin.x = NSMaxX( bbox );
82.                                 [tfm translateXBy:origin.x yBy:origin.y];
83.                                 [tfm rotateByDegrees:90];
84.                                 [tfm translateXBy:-origin.x yBy:-origin.y];
85.                         }
86.                         else
87.                         {
88.                                 origin.y = NSMaxY( bbox );
89.                                 [tfm translateXBy:origin.x yBy:origin.y];
90.                                 [tfm rotateByDegrees:-90];
91.                                 [tfm translateXBy:-origin.x yBy:-origin.y];
92.                         }
93.                         [tfm concat];
94.                 }
95.                 
96.                 [std drawAtPoint:origin];
97.                 [NSGraphicsContext restoreGraphicsState];
98.         }
99. }

    我想要做的是基本的，旋转的形象在NSView 。找不到任何例子或者信息是很简单对我来说，把握好这一点。我认为这必须做的NSAffineTransform 。最接近我可以以我个人的是运用变换和获得的图像旋转，但我只得到右上角的图片显示/旋转。

NSAffineTransform *transform = [NSAffineTransform transform];
[transform translateXBy:0.5f * [image width] yBy:0.5f * [image height]];
[transform rotateByDegrees:45.0f];
[transform translateXBy:-0.5f * [image width] yBy:-0.5f * [image height]];
[NSGraphicsContext saveGraphicsState];
[transform concat];
[image compositeToPoint:NSMakePoint(0.0f, 0.0f) operation:NSCompositeSourceOver];
[NSGraphicsContext restoreGraphicsState];

这个工程非常不错。我变化一下，下面的任何人都感兴趣。

NSAffineTransform *transform = [NSAffineTransform transform];
[transform translateXBy:0.5f * [image width] yBy:0.5f * [image height]];
[transform rotateByDegrees:45.0f];
[transform translateXBy:-0.5f * [image width] yBy:-0.5f * [image height]];
[NSGraphicsContext saveGraphicsState];
[transform concat];

//[image compositeToPoint:NSMakePoint(0.0f, 0.0f) operation:NSCompositeSourceOver];
[image drawAtPoint:NSMakePoint(0.0f, 0.0f) fromRect:[self bounds] operation:NSCompositeSourceOver fraction:1];
[NSGraphicsContext restoreGraphicsState];

 

1. #import <Cocoa/Cocoa.h>
2. @interface UFOView : NSView {
3.     float angle;
4.     NSBezierPath *path; 
5. }
6. @end
8. //helper - gives center of rectangle
9. static NSPoint MidRect(NSRect rect) { return NSMakePoint(NSMidX(rect), NSMidY(rect)); }
11. @implementation UFOView
12. - (void)awakeFromNib {
13.     path = [[NSBezierPath bezierPath] retain]; //cache to save recreating
14.     [path moveToPoint:NSMakePoint(-22, -30)];
15.     [path lineToPoint:NSMakePoint(-2, 30)];
16.     [path lineToPoint:NSMakePoint(28, -30)];
17.     [path lineToPoint:NSMakePoint(-35, 8)];
18.     [path lineToPoint:NSMakePoint(35, 8)];
19.     [path closePath];
20.     [NSTimer scheduledTimerWithTimeInterval:1.0/24 target:self selector:@selector(singleStep:) userInfo:nil repeats:YES];
21. }
22. - (void)dealloc {
23.     [path release];
24.     [super dealloc];
25. }
26. - (void)singleStep:(NSTimer *)timer {
27.     angle += 5.0;
28.     [self setNeedsDisplay:YES];
29. }
30. - (void)drawRect:(NSRect)rect { // unless you specify opaque it clears the view for you
31.     NSPoint pathCenter  = MidRect([path bounds]); // could cache this too...
32.     NSPoint viewCenter = MidRect([self bounds]);
33.     
34.     NSAffineTransform *transform = [NSAffineTransform transform]; // it will autorelease
35.     [transform translateXBy:viewCenter.x yBy:viewCenter.y];
36.     [transform rotateByDegrees:angle];
37.     [transform translateXBy:-pathCenter.x yBy:-pathCenter.y];
39.     // alternatively to creating a new path is to [transform concat] and just draw...
40.     NSBezierPath *drawPath = [transform transformBezierPath:path]; // it will autorelease
41.     [[NSColor lightGrayColor] setFill];
42.     [[NSColor blackColor] setStroke];
43.     [drawPath fill];
44.     [drawPath stroke];
45. }
46. @end