How to find out uncoloured area uibeizerpath?

问题

That greycolour is UIImageView and the White colour font is Image.

That image Placed inside UIImageView.

I like to colour only inside the font ,not an whole UIImageview for that i am going to find out the coordinates of the image .

i am new to this kind of concept so kindly some one guide me how to colour only inside the image ,there are 50+ images is there ,it is not static so give some good idea .

This is the code i am using to draw inside the UIImageView:

-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{

    UITouch *touch = [[event allTouches] anyObject];
    touchPoint = [touch locationInView:self.imgColor];

        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
        [path addLineToPoint:CGPointMake(startingPoint.x,startingPoint.y)];


        startingPoint=touchPoint;
        CAShapeLayer *shapeLayer = [CAShapeLayer layer];
        shapeLayer.path = [path CGPath];
        shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
        shapeLayer.lineWidth = 3.0;
        shapeLayer.fillColor = [[UIColor redColor] CGColor];
        [self.imgColor.layer addSublayer:shapeLayer];
        [arrLayer addObject:shapeLayer];

    NSLog(@"Touch moving point =x : %f Touch moving point =y : %f", touchPoint.x, touchPoint.y);



}

回答1:

Use this custom UIImage view:

CustomView.h

@interface CustomView : UIImageView

@end

CustomView.m

@interface CustomView ()
{
    CGPoint touchPoint,startingPoint;
    UIView *drawingView;
}

@end


@implementation CustomView

-(void)awakeFromNib
{
    drawingView = [[UIView alloc] initWithFrame:self.bounds];
    drawingView.backgroundColor = [UIColor clearColor];
    [self addSubview:drawingView];
    [self updateMask];
}

- (void)updateMask
{
    CALayer *maskLayer = [CALayer layer];
    maskLayer.geometryFlipped = YES;
    maskLayer.contents = (id)self.image.CGImage;
    switch (self.contentMode)
    {
        case UIViewContentModeScaleToFill:
            maskLayer.contentsGravity = kCAGravityResize;
            break;
        case UIViewContentModeScaleAspectFit:
            maskLayer.contentsGravity = kCAGravityResizeAspect;
            break;
        case UIViewContentModeScaleAspectFill:
            maskLayer.contentsGravity = kCAGravityResizeAspectFill;
            break;
        case UIViewContentModeCenter:
            maskLayer.contentsGravity = kCAGravityCenter;
            break;
        case UIViewContentModeTop:
            maskLayer.contentsGravity = kCAGravityTop;
            break;
        case UIViewContentModeBottom:
            maskLayer.contentsGravity = kCAGravityBottom;
            break;
        case UIViewContentModeLeft:
            maskLayer.contentsGravity = kCAGravityLeft;
            break;
        case UIViewContentModeRight:
            maskLayer.contentsGravity = kCAGravityRight;
            break;
        case UIViewContentModeTopLeft:
            maskLayer.contentsGravity = kCAGravityTopLeft;
            break;
        case UIViewContentModeTopRight:
            maskLayer.contentsGravity = kCAGravityTopRight;
            break;
        case UIViewContentModeBottomLeft:
            maskLayer.contentsGravity = kCAGravityBottomLeft;
            break;
        case UIViewContentModeBottomRight:
            maskLayer.contentsGravity = kCAGravityBottomRight;
            break;
        default:
            break;
    }
    maskLayer.frame = drawingView.bounds;
    drawingView.layer.mask = maskLayer;
}


- (void)setImage:(UIImage *)image
{
    [super setImage:image];
    [self updateMask];
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    drawingView.frame = self.bounds;
    drawingView.layer.mask.frame = drawingView.bounds;
}


-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];
    touchPoint = [touch locationInView:self];

    if (!CGPointEqualToPoint(startingPoint, CGPointZero))
    {
        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:CGPointMake(touchPoint.x,touchPoint.y)];
        [path addLineToPoint:CGPointMake(startingPoint.x,startingPoint.y)];

        CAShapeLayer *shapeLayer = [CAShapeLayer layer];
        shapeLayer.path = [path CGPath];
        shapeLayer.strokeColor = [[UIColor blueColor] CGColor];
        shapeLayer.lineWidth = 3.0;
        shapeLayer.fillColor = [[UIColor redColor] CGColor];
        [drawingView.layer addSublayer:shapeLayer];
    }
    startingPoint=touchPoint;

//    [arrLayer addObject:shapeLayer];
    NSLog(@"Touch moving point =x : %f Touch moving point =y : %f", touchPoint.x, touchPoint.y);
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
{
    startingPoint = CGPointZero;
}


@end

来源：https://stackoverflow.com/questions/34736949/how-to-find-out-uncoloured-area-uibeizerpath

标签

ios

objective-c

uibezierpath

cgpoint