Images and Mouse Events(Chapter 18 of Cocoa Programming for Mac OS X)

nawawa001

1 #import "StretchView.h"
  2
  3
  4 @implementation StretchView
  5
  6 - (id)initWithFrame:(NSRect)rect
  7 {
  8     if (![super initWithFrame:rect])
  9     {
10         return nil;
11     }
12     
13     srandom(time(NULL));
14     
15     path = [[NSBezierPath alloc] init];
16     [path setLineWidth:3.0];
17     NSPoint p = [self randomPoint];
18     [path moveToPoint:p];
19     int i;
20     for(i=0;i<15;i++)
21     {
22         p = [self randomPoint];
23         [path lineToPoint:p];
24     }
25     [path closePath];
26     opacity = 1.0;
27     return self;
28 }
29
30 - (void)dealloc
31 {
32     [path release];
33     [image release];
34     [super dealloc];
35 }
36
37 - (NSPoint)randomPoint
38 {
39     NSPoint result;
40     NSRect r = [self bounds];
41     result.x = r.origin.x + random() % (int)r.size.width;
42     result.y = r.origin.y + random() % (int)r.size.height;
43     return result;
44 }
45
46 - (void)drawRect:(NSRect)dirtyRect
47 {
48     NSRect bounds = [self bounds];
49     [[NSColor greenColor] set];
50     [NSBezierPath fillRect:bounds];
51     
52     [[NSColor whiteColor] set];
53     [path fill];
54     if(image)
55     {
56         NSRect imageRect;
57         imageRect.origin = NSZeroPoint;
58         imageRect.size = [image size];
59         NSRect drawingRect = [self currentRect];
60         [image drawInRect:drawingRect fromRect:imageRect operation:NSCompositeSourceOver fraction:opacity];
61     }
62 }
63
64 - (void)mouseDown:(NSEvent *)event
65 {
66     NSPoint p =[event locationInWindow];
67     downPoint = [self convertPoint:p fromView:nil];
68     currentPoint = downPoint;
69     [self setNeedsDisplay:YES];
70     NSLog(@"mouseDown: %d", [event clickCount]);
71 }
72
73 - (void)mouseDragged:(NSEvent *)event
74 {
75     NSPoint p = [event locationInWindow];
76     currentPoint = [self convertPoint:p fromView:nil];
77     [self setNeedsDisplay:YES];
78     NSLog(@"mouseDragged: %@", NSStringFromPoint(p));
79 }
80
81 - (void)mouseUp:(NSEvent *)event
82 {
83     NSPoint p = [event locationInWindow];
84     currentPoint = [self convertPoint:p fromView:nil];
85     [self setNeedsDisplay:YES];
86     NSLog(@"mouseUp:");
87 }
88
89 - (NSRect)currentRect
90 {
91     float minX = MIN(downPoint.x, currentPoint.x);
92     float maxX = MAX(downPoint.x, currentPoint.x);
93     float minY = MIN(downPoint.y, currentPoint.y);
94     float maxY = MIN(downPoint.y, currentPoint.y);
95     
96     return NSMakeRect(minX, minY, maxX-minX, maxY-minY);
97 }
98
99 #pragma mark Accesors
100
101 - (void)setImage:(NSImage *)newImage
102 {
103     [newImage retain];
104     
105     [image release];
106     image = newImage;
107     NSSize imageSize = [newImage size];
108     downPoint = NSZeroPoint;
109     currentPoint.x = downPoint.x + imageSize.width;
110     currentPoint.y = downPoint.y + imageSize.height;
111     [self setNeedsDisplay:YES];
112 }
113
114 - (float)opacity
115 {
116     return opacity;
117 }
118
119 - (void)setOpacity:(float)x
120 {
121     opacity = x;
122     [self setNeedsDisplay:YES];
123 }
124
125 @end