Question

我正在使用CGContext创建一个带有四个给定点的简单正方形（这些点应该是一个完美的正方形）。然而，iPad应用程序不是200px x 200px的平方，而是看起来像是680w乘300h。我错过了什么吗？

int beginPointX, beginPointY, gridSize, gridPadding;

gridSize = 200;
gridPadding = 10;

beginPointX = gridPadding; // padding from left border
beginPointY = gridPadding; // padding from top border


// initiate UIGraphics method
UIGraphicsBeginImageContext(self.view.frame.size);

// set context for our UIGraphics method
CGContextRef context = UIGraphicsGetCurrentContext();

// set some defaults for our CGContext
CGContextSetRGBStrokeColor(context, 0.0, 0.0, 0.0, 1.0);
CGContextSetLineWidth(context, 1.0);
CGContextBeginPath(context);


// start

// build outer box
CGRect testRect = CGRectMake(beginPointX, beginPointY, (beginPointX + gridSize), (beginPointY + gridSize));
CGContextAddRect(context, testRect);
CGContextStrokePath(context);

/*
NSLog(@"Line from %dx%d to %dx%d", beginPointX, beginPointY, beginPointX, (beginPointY + gridSize));
CGContextMoveToPoint(context, beginPointX, beginPointY);
CGContextAddLineToPoint(context, beginPointX, (beginPointY + gridSize));
CGContextStrokePath(context);

NSLog(@"Line from %dx%d to %dx%d", beginPointX, (beginPointY + gridSize), (beginPointX + gridSize), (beginPointY + gridSize));
CGContextMoveToPoint(context, beginPointX, (beginPointY + gridSize));
CGContextAddLineToPoint(context, (beginPointX + gridSize), (beginPointY + gridSize));
CGContextStrokePath(context);

NSLog(@"Line from %dx%d to %dx%d", (beginPointX + gridSize), (beginPointY + gridSize), (beginPointX + gridSize), beginPointY);
CGContextMoveToPoint(context, (beginPointX + gridSize), (beginPointY + gridSize));
CGContextAddLineToPoint(context, (beginPointX + gridSize), beginPointY);
CGContextStrokePath(context);

NSLog(@"Line from %dx%d to %dx%d", (beginPointX + gridSize), beginPointY, beginPointX, beginPointY);
CGContextMoveToPoint(context, (beginPointX + gridSize), beginPointY);
CGContextAddLineToPoint(context, beginPointX, beginPointY);
CGContextStrokePath(context);
*/

// insert set of instructions into our grid pointer
grid.image = UIGraphicsGetImageFromCurrentImageContext();

有一点需要注意的是，我正在开发一个iPad应用程序，它的方向被锁定在格局中（如果这有任何区别）。

Answer 1

CGRect CGRectMake (
   CGFloat x,
   CGFloat y,
   CGFloat width,
   CGFloat height
);

所以，这一行

CGRect testRect = CGRectMake(beginPointX, beginPointY, (beginPointX + gridSize), (beginPointY + gridSize));

应该是

CGRect testRect = CGRectMake(beginPointX, beginPointY, gridSize, gridSize);

CGContext宽度似乎过度拉伸

1 个答案: