[Cocoa]_[画直线、矩形、文字]

    总结Cocoa下画直线、矩形、文字的方法，在界面开发种经常会遇到。要掌握Cocoa画图，首先要知道，NSPoint和NSRect,一个保存坐标点，一个保存一个矩形坐标和长宽，还要明白Cocoa的画布是NSView类，画笔是NSBezierPath类，画图都是通过NSBezierPath这个类对象来实现绘图。

第二种方法：

一个Graphics Context表示一个绘制目标。它包含绘制系统用于完成绘制指令的绘制参数和设备相关信息。Graphics Context定义了基本的绘制属性，如颜色、裁减区域、线条宽度和样式信息、字体信息、混合模式等。

我们可以通过几种方式来获取Graphics Context：Quartz提供的创建函数、Mac OS X框架或IOS的UIKit框架提供的函数。Quartz提供了多种Graphics Context的创建函数，包括bitmap和PDF，我们可以使用这些Graphics Context创建自定义的内容。

1.画直线，有四种方法。

    //(1)直线的本质是一个高度较小的矩形
    NSRect rect5 = NSMakeRect(50, 70, 1, 250);
    NSBezierPath *path1 = [NSBezierPath bezierPathWithRect:rect5];
    [[NSColor redColor] set];
    [path1 fill];
    
    //(2)通过两个点画直线
    NSBezierPath *path = [NSBezierPath bezierPath];
    NSPoint pt1 = NSMakePoint(50, 70);
    NSPoint pt2 = NSMakePoint(350, 0);
    [path moveToPoint:pt1];
    [path relativeLineToPoint:pt2];
    [path setLineWidth:1];
    [[NSColor blueColor] set];
    [path stroke];
    
    //(3)无需画笔，直接填充
    [[NSColor yellowColor] set];
    NSRect lineRect = NSMakeRect(50, 320, 350, 1);
    NSRectFill(lineRect);
    
    //(4)CGContentext
    CGContextRef myContext = [[NSGraphicsContext  currentContext] graphicsPort];
    CGContextSetRGBFillColor (myContext, 0, 255, 0, 1);
    CGContextFillRect (myContext, CGRectMake (400, 70, 1, 250 ));

画表格示例：

    for (int i =20; i < 240; i += 20) {
        NSRect lineRect1 = NSMakeRect(20, i, 200, 1);
        NSRectFill(lineRect1);
        
        NSRect lineRect2 = NSMakeRect(i, 20, 1, 200);
        NSRectFill(lineRect2);
    }

2.画虚线

    //(1)
    NSBezierPath *path = [NSBezierPath bezierPath];
    CGFloat array[2];
    array[0] = 3.0;
    array[1] = 1.0;
    
    [path setLineDash:array count:2 phase:0];
    NSPoint pt1 = NSMakePoint(50, 200);
    NSPoint pt2 = NSMakePoint(300, 0);
    [path moveToPoint:pt1];
    [path relativeLineToPoint:pt2];
    [path setLineWidth:1];
    [[NSColor redColor] set];
    [path stroke];
    
    //(2)
    CGContextRef context = [[NSGraphicsContext currentContext] graphicsPort];
    CGContextSetLineWidth(context, 1);
    
    CGFloat dashArray[] = {3,1};
    
    CGContextSetLineDash(context, 1, dashArray, 1);//跳过3个再画虚线，所以刚开始有6-（3-2）=5个虚点
    
    CGContextMoveToPoint(context, 50, 100);
    
    CGContextAddLineToPoint(context, 350, 100);
    
    CGContextStrokePath(context);

3.画矩形

    //2.画矩形
    
    //(1)NSBezierPath
    NSRect rect1 = NSMakeRect(200, 200, 50, 50);
    NSBezierPath *thePath1 = [NSBezierPath bezierPathWithRect:rect1];
    NSColor *theColor1 = [NSColor redColor];
    [theColor1 set];
    [thePath1 fill];
    
    //(2)无需画笔，直接填充
    [[NSColor blackColor] set];
    NSRect rect2 = NSMakeRect(250, 100, 150, 45);
    NSRectFill(rect2);
    
    //(3)CGContent
    CGContextRef myContext2 = [[NSGraphicsContext  currentContext] graphicsPort];
    CGContextSetRGBFillColor (myContext2, 255, 0, 255, 1);
    CGContextFillRect (myContext2, CGRectMake (100, 100, 150, 45 ));

4.画椭圆

    //3.画椭圆
    //(1)
    NSBezierPath *path3 = [NSBezierPath bezierPathWithOvalInRect:NSMakeRect(150, 150, 100, 50)];
    [[NSColor whiteColor] set];
    [path3 fill];
    //(2)
    //可通过两个参数来控制边角的弧度
    NSBezierPath *path2 = [NSBezierPath bezierPathWithRoundedRect:NSMakeRect(150, 200, 100, 50) xRadius:90 yRadius:90];
    [[NSColor lightGrayColor] set];
    [path2 fill];
    
    //(3)
    CGContextRef ctx = [[NSGraphicsContext currentContext] graphicsPort];
    CGContextAddEllipseInRect(ctx, NSMakeRect(150, 250, 100, 50));
    CGContextSetRGBFillColor(ctx, 255, 255, 0, 1);
    CGContextFillPath(ctx);

5.画圆

    //(1)
    NSBezierPath *path3 = [NSBezierPath bezierPathWithOvalInRect:NSMakeRect(150, 50, 100, 100)];
    [[NSColor whiteColor] set];
    [path3 fill];
    //(2)
    //可通过两个参数来控制边角的弧度
    NSBezierPath *path2 = [NSBezierPath bezierPathWithRoundedRect:NSMakeRect(150, 150, 100, 100) xRadius:90 yRadius:90];
    [[NSColor lightGrayColor] set];
    [path2 fill];
    
    //(3)
    CGContextRef ctx = [[NSGraphicsContext currentContext] graphicsPort];
    CGContextAddEllipseInRect(ctx, NSMakeRect(150, 250, 100, 100));
    CGContextSetRGBFillColor(ctx, 255, 255, 0, 1);
    CGContextFillPath(ctx);

6.画三角形

    NSBezierPath *path = [NSBezierPath bezierPath];
    NSPoint pt1 = NSMakePoint(50, 50);
    NSPoint pt2 = NSMakePoint(50, 50);
    NSPoint pt3 = NSMakePoint(50, -50);
    NSPoint pt4 = NSMakePoint(-100, 0);
    [path moveToPoint:pt1];
    [path relativeLineToPoint:pt2];
    [path relativeLineToPoint:pt3];
    [path relativeLineToPoint:pt4];
    [path stroke];
    
    [[NSColor redColor] set];
    [path fill];

7画文字

    //4.画字体
    
    //(1)NSString绘制字符串
    NSString * s1 = @"hello wrold";
    NSMutableDictionary *md = [NSMutableDictionary dictionary];
    //字体类型和大小
    [md setObject:[NSFont fontWithName:@"Arial" size:20] forKey:NSFontAttributeName];
    //字体颜色
    [md setObject:[NSColor yellowColor] forKey:NSForegroundColorAttributeName];
    [s1 drawAtPoint:NSMakePoint(200, 300) withAttributes:md];
    
    //(2)NSMutableAttributedString绘制带属性字符串
    NSMutableAttributedString *s = [[NSMutableAttributedString alloc] initWithString:@"Big Nerd Ranch"];
    //字体类型和大小
    [s addAttribute:NSFontAttributeName value:[NSFont fontWithName:@"Arial Black" size:22] range:NSMakeRange(0,14)];
    //给字体加下划线
    [s addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInt:1] range:NSMakeRange(0,3)];
    //字体颜色
    [s addAttribute:NSForegroundColorAttributeName value:[NSColor greenColor] range:NSMakeRange(0,8)];
    //上下移动
    [s addAttribute:NSSuperscriptAttributeName value:[NSNumber numberWithInt:1] range:NSMakeRange(0, 5)];
    [s drawInRect:[self bounds]];
    
    //(3)CGContext
    
    NSPoint point = NSMakePoint(80, 80);
    CGContextRef myContext = [[NSGraphicsContext currentContext] graphicsPort];
    CGContextSelectFont (myContext, "Helvetica-Bold",1,kCGEncodingMacRoman);
    CGContextSetCharacterSpacing (myContext, 0.5);
    CGContextSetTextDrawingMode (myContext, kCGTextFill);    
    CGContextSetRGBFillColor (myContext, 0, 1, 0, 0.5);
    CGContextShowTextAtPoint (myContext,point.x , point.y, "www.google.com", 14);

也可以直接画在控件上，像如下：

    NSMutableAttributedString *s = [[NSMutableAttributedString alloc] initWithString:@"Big Nerd Ranch"];
    //字体大小
    [s addAttribute:NSFontAttributeName value:[NSFont fontWithName:@"Arial Black" size:22] range:NSMakeRange(0,14)];
    //给字体加下划线
    [s addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInt:1] range:NSMakeRange(0,3)];
    //字体颜色
    [s addAttribute:NSForegroundColorAttributeName value:[NSColor greenColor] range:NSMakeRange(0,8)];
    //上下移动
    [s addAttribute:NSSuperscriptAttributeName value:[NSNumber numberWithInt:1] range:NSMakeRange(0, 5)];
    
    [button setAttributedTitle:s];
    [label setAttributedStringValue:s];

附上项目代码下载地址：http://download.csdn.net/detail/yepeng2014/9181177