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xcode - 在 Xcode for Titanium 中绘制线条不透明度

转载 作者:行者123 更新时间:2023-12-04 21:44:45 25 4
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我是 xCode 的新手,但遇到了问题。我正在为我的 Ipad 申请。我想突出显示文本,但无法设置线条的不透明度。我在网上搜索过,但没有找到任何相关信息。现在我正在使用这个 drawImage.alpha = lineOpacity;但这并不好,我之前绘制的所有内容都会变得不透明。我只想在新绘制时完成 alpha。我现在正在使用这段代码:

   //here I init the opacity
-(id)init
{
if (self = [super init])
{
strokeWidth = 5;
strokeColor = CGColorRetain([[TiUtils colorValue:@"#000"] _color].CGColor);
lineOpacity = 1;
}
return self;
}
- (void)dealloc
{
RELEASE_TO_NIL(drawImage);
CGColorRelease(strokeColor);
[super dealloc];
}

- (void)frameSizeChanged:(CGRect)frame bounds:(CGRect)bounds
{
[super frameSizeChanged:frame bounds:bounds];
if (drawImage!=nil)
{
[drawImage setFrame:bounds];
}
}

//here I add a call
- (void)setLineOpacity_:(id)alpha
{
lineOpacity = [TiUtils floatValue:alpha];
}

//here I want to set the opacity
- (void)drawAt:(CGPoint)currentPoint
{
UIView *view = [self imageView];
UIGraphicsBeginImageContext(view.frame.size);
[drawImage.image drawInRect:CGRectMake(0, 0, view.frame.size.width, view.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), strokeWidth);
CGContextSetStrokeColorWithColor(UIGraphicsGetCurrentContext(), strokeColor);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
//here i want to set the alpha, but everything I draw before get also the new alpha.
//I just want the alpha to be done on the new draw
drawImage.alpha = lineOpacity;
drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
lastPoint = currentPoint;
}

我希望有人能帮助我。提前致谢。

编辑:我用它来画画:

- (UIImageView*)imageView
{
if (drawImage==nil)
{
drawImage = [[UIImageView alloc] initWithImage:nil];
drawImage.frame = [self bounds];
[self addSubview:drawImage];
}
return drawImage;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event];

UITouch *touch = [touches anyObject];
lastPoint = [touch locationInView:[self imageView]];
lastPoint.y -= 20;
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesMoved:touches withEvent:event];

UITouch *touch = [touches anyObject];
CGPoint currentPoint = [touch locationInView:[self imageView]];
currentPoint.y -= 20;
[self drawAt:currentPoint];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesEnded:touches withEvent:event];
[self drawAt:lastPoint];
}

#pragma mark Public APIs

- (void)setStrokeWidth_:(id)width
{
strokeWidth = [TiUtils floatValue:width];
}

- (void)setStrokeColor_:(id)value
{
CGColorRelease(strokeColor);
TiColor *color = [TiUtils colorValue:value];
strokeColor = [color _color].CGColor;
CGColorRetain(strokeColor);
}

- (void)setLineOpacity_:(id)alpha
{
lineOpacity = [TiUtils floatValue:alpha];
}

我真的很想找出它行不通的方法,搜索了很长时间。

最佳答案

你可以像这样制作一个 UIColor 并从中获取 CGColorRef:

strokeColor = CGColorRetain([UIColor colorWithRed:1.0f green:1.0f blue:0.0f alpha:0.5f].CGColor);

关于xcode - 在 Xcode for Titanium 中绘制线条不透明度,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5708245/

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