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How to draw a line like chalk?

I want to draw a line like chalk. And the edge of the line is weak. Just like using chalk, draw on the blackboard.

How do i get this? Now I drew a line using the image, but on the board it does not look like drawing, because the line is not weak. Please give me some advice.

Here is my code:

    for (NSDictionary *dictStroke in self.arrayStrokes)
    {
        NSArray *arrayPointsInstroke = [dictStroke objectForKey:@"points"];
        //UIColor *color = [dictStroke objectForKey:@"color"];

    UIColor *color = [UIColor colorWithPatternImage:[UIImage imageNamed:@"point.png"]];

        float size = [[dictStroke objectForKey:@"size"] floatValue];
        [color setStroke];      // equivalent to both setFill and setStroke

        // draw the stroke, line by line, with rounded joints
        UIBezierPath* pathLines = [UIBezierPath bezierPath];
        CGPoint pointStart = CGPointFromString([arrayPointsInstroke objectAtIndex:0]);
        [pathLines moveToPoint:pointStart];
        for (int i = 0; i < (arrayPointsInstroke.count - 1); i++)
        {
            CGPoint pointNext = CGPointFromString([arrayPointsInstroke objectAtIndex:i+1]);
            [pathLines addLineToPoint:pointNext];
        }
        pathLines.lineWidth = size;
        pathLines.lineJoinStyle = kCGLineJoinRound;
        pathLines.lineCapStyle = kCGLineCapRound;
        [pathLines stroke];

        arraynum++;
    }
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1 answer

Try using an image of a zebra line pattern. This would give you an effect, like writing little things.

brushPattern = [[UIColor alloc]initWithPatternImage: [UIImage imageNamed:@"pattern.jpg"]];

- (void)drawRect:(CGRect)rect
{
    [brushPattern setStroke];
    [myPath strokeWithBlendMode:kCGBlendModeNormal alpha:1.0]; // myPath - points to be drawn    
}
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