IOS开发（85）之缩放图像

1 前言
使用 cgaffinetransformmakescale/cgcontextscalectm 函数创建一个仿射缩放变换。

2 代码实例
zyviewcontrollerview.m

 

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- (void)drawrect:(cgrect)rect{ 
    cgmutablepathref path = cgpathcreatemutable(); 
    cgrect rectangle = cgrectmake(10.0f, 10.0f, 200.0f, 
                                  300.0f); 
    //将矩形缩放0.5 
    cgaffinetransform transform = cgaffinetransformmakescale(0.5f, 0.5f); 
    /* add the rectangle to the path */ 
    cgpathaddrect(path,&transform, rectangle); 
    /* get the handle to the current context */ 
    cgcontextref currentcontext = uigraphicsgetcurrentcontext(); 
    /* add the path to the context */ 
    cgcontextaddpath(currentcontext,path); 
    /* set the fill color to cornflower blue */ 
    [[uicolor colorwithred:0.20f green:0.60f blue:0.80f alpha:1.0f] setfill]; 
    /* set the stroke color to brown */ 
    [[uicolor browncolor] setstroke]; 
    /* set the line width (for the stroke) to 5 */ 
    cgcontextsetlinewidth(currentcontext,5.0f); 
    /* stroke and fill the path on the context */ 
    cgcontextdrawpath(currentcontext,kcgpathfillstroke); 
    /* dispose of the path */ 
    cgpathrelease(path); 
}