使文字在核心图形中上下颠倒 [英] getting the text up-side down in core graphic
本文介绍了使文字在核心图形中上下颠倒的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我正在通过以下方式在核心图形中绘制文本
-(void)drawRect:(CGRect)rect {
CGContextTranslateCTM(context,20,150);
CGContextScaleCTM(context,1,1);
//使用MyDrawText函数绘制文本
myDrawText(context,viewBounds);
}
void myDrawText(CGContextRef myContext,CGRect contextRect)
{
CGFloat w,h;
w = contextRect.size.width;
h = contextRect.size.height;
CGAffineTransform myTextTransform;
CGContextSelectFont(myContext,
Helvetica-Bold,
h / 12,
kCGEncodingMacRoman);
CGContextSetCharacterSpacing(myContext,.5);
CGContextSetTextDrawingMode(myContext,kCGTextFill);
CGContextSetRGBFillColor(myContext,1,1,1,1);
myTextTransform = CGAffineTransformMakeRotation(0);
CGContextSetTextMatrix(myContext,myTextTransform);
CGContextShowTextAtPoint(myContext,115,0,成功,10);
}
运行后,我得到的文字上下颠倒,如下所示
为什么
请在此问题上向我提出建议。
解决方案
这是翻转它的方法。只需在drawRect中添加2行
-(void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext ();
CGContextTranslateCTM(context,20,150);
CGContextScaleCTM(context,1,1);
CGAffineTransform flipVertical = CGAffineTransformMake(1,0,0,-1,0,0);
CGContextConcatCTM(context,flipVertical);
//使用MyDrawText函数绘制文本
myDrawText(context,self.bounds);
}
I am drawing a text in core graphic by following
- (void)drawRect:(CGRect)rect {
CGContextTranslateCTM(context, 20, 150);
CGContextScaleCTM(context, 1, 1);
// Draw the text using the MyDrawText function
myDrawText(context, viewBounds);
}
void myDrawText (CGContextRef myContext, CGRect contextRect)
{
CGFloat w, h;
w = contextRect.size.width;
h = contextRect.size.height;
CGAffineTransform myTextTransform;
CGContextSelectFont (myContext,
"Helvetica-Bold",
h/12,
kCGEncodingMacRoman);
CGContextSetCharacterSpacing (myContext, .5);
CGContextSetTextDrawingMode (myContext, kCGTextFill);
CGContextSetRGBFillColor (myContext, 1, 1, 1, 1);
myTextTransform = CGAffineTransformMakeRotation (0);
CGContextSetTextMatrix (myContext, myTextTransform);
CGContextShowTextAtPoint (myContext, 115, 0, "Successful", 10);
}
After running it I am getting the text is in up-side down like below
Why the text is up side down after the drawing
Please advice me on this issue.
解决方案
this is the way to flip it. Just add 2 lines to your drawRect
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(context, 20, 150);
CGContextScaleCTM(context, 1, 1);
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, 0);
CGContextConcatCTM(context, flipVertical);
// Draw the text using the MyDrawText function
myDrawText(context, self.bounds);
}
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