在uidraw中更改顏色更改

Question

嗨，有沒有什麼辦法可以用按鈕以編程方式更改顏色？

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-(void)drawToBuffer { 

//     Red Gr Blu Alpha 
CGFloat color[4] = {0.0, 0.0, 0.0, 1.0}; 


if (self.previousPoint != nil) { 
    CGContextSetRGBStrokeColor(offScreenBuffer, color[0], color[1], color[2], color[3]); 

    CGContextBeginPath(offScreenBuffer); 
    CGContextSetLineWidth(offScreenBuffer, 5.0); 
    CGContextSetLineCap(offScreenBuffer, kCGLineCapRound); 

    CGContextMoveToPoint(offScreenBuffer, previousPoint.location.x, previousPoint.location.y); 
    CGContextAddLineToPoint(offScreenBuffer, point.location.x, point.location.y); 

    CGContextDrawPath(offScreenBuffer, kCGPathStroke); 
} 

}

這屬於uidraw視圖和IM希望在我的應用程序

Answer 1

只是顏色值更改爲白色以創建一個UiDraw橡皮擦功能...即改變顏色[4] = {1.0,1.0,1.0,1.0}這是白色的... ...

顏色需要r，g，b，a作爲顏色分量範圍從0.0到1.0浮點值或1到int值爲255。組件a代表透明度。