Demo of three-color paint brushes and erasers for ios

Demo function: three-color paint brush and eraser board demo [tested on iphone 6.1]

Demo Description: In the project, PaintView. m is the drawing board of the demo. PaintView and three color buttons are added to the view of ViewController. The main interface of the program.

Demo screenshot:

 

 

Demo main code: PaintView. m canvas view

[Csharp]
# Import "PaintView. h"
# Import <QuartzCore/QuartzCore. h>
 
@ Implementation PaintView
@ Synthesize paintColor = _ paintColor;
@ Synthesize erase;
-(Id) initWithFrame :( CGRect) frame
{
Self = [super initWithFrame: frame];
If (self ){
Self. layer. shadowColor = [UIColor blackColor]. CGColor;
Self. layer. shadowOpacity = 0.8;
Self. layer. shadowOffset = CGSizeMake (5, 5 );
Self. backgroundColor = [UIColor whiteColor];
Self. paintColor = [UIColor blackColor];
// Initialization code
LinesArray = [[NSMutableArray alloc] init];
UIPanGestureRecognizer * panGesture = [[UIPanGestureRecognizer alloc] initWithTarget: self
Action: @ selector (panGesture :)];
[Self addGestureRecognizer: panGesture];
[PanGesture release];
}
Return self;
}
 
-(Void) dealloc {
[LinesArray release];
[_ PaintColor release];
[Super dealloc];
}
 
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
-(Void) drawRect :( CGRect) rect
{
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext ();
CGContextSetLineWidth (context, 20 );
// NSLog (@ "color: % @", _ paintColor );
 
For (NSDictionary * lineDic in linesArray ){
UIColor * lineColor = [lineDic objectForKey: @ "color"];
CGContextSetStrokeColorWithColor (context, lineColor. CGColor );
CGMutablePathRef paintPath = CGPathCreateMutable ();
NSArray * linePointArray = [lineDic objectForKey: @ "line"];
For (NSInteger I = 0; I <linePointArray. count; I ++ ){
CGPoint point = [[linePointArray objectAtIndex: I] CGPointValue];
If (I = 0 ){
// CGContextMoveToPoint (context, point. x, point. y );
CGPathMoveToPoint (paintPath, NULL, point. x, point. y );
} Else {
// CGContextAddLineToPoint (context, point. x, point. y );
CGPathAddLineToPoint (paintPath, NULL, point. x, point. y );
}
}
CGContextAddPath (context, paintPath );
CGContextStrokePath (context );

If ([lineDic objectForKey: @ "eraseArray"]) {
// NSLog (@ "color: % @", lineColor );
NSMutableArray * eraseArray = [lineDic objectForKey: @ "eraseArray"];
CGContextSetStrokeColorWithColor (context, [UIColor whiteColor]. CGColor );
CGMutablePathRef paintPath = CGPathCreateMutable ();
For (NSInteger I = 0; I <eraseArray. count; I ++ ){
CGPoint point = [[eraseArray objectAtIndex: I] CGPointValue];
// NSLog (@ "erase point: % @", NSStringFromCGPoint (point ));
If (I = 0 ){
// CGContextMoveToPoint (context, point. x, point. y );
CGPathMoveToPoint (paintPath, NULL, point. x, point. y );
} Else {
// CGContextAddLineToPoint (context, point. x, point. y );
CGPathAddLineToPoint (paintPath, NULL, point. x, point. y );
}
}
CGContextAddPath (context, paintPath );
CGContextStrokePath (context );
}
}
}
 
 
-(Void) panGesture :( UIPanGestureRecognizer *) thePan {
CGPoint touchPoint = [thePan locationInView: self];
If (self. erase ){
If (thePan. state = UIGestureRecognizerStateChanged ){
For (NSMutableDictionary * lineDic in linesArray ){
NSMutableArray * linePointArray = [lineDic objectForKey: @ "line"];
For (NSInteger I = 0; I <linePointArray. count; I ++ ){
CGPoint point = [[linePointArray objectAtIndex: I] CGPointValue];
CGFloat distance = powf (point. x-touchPoint.x, point. y-touchPoint.y );
If (distance <20 ){
NSMutableArray * eraseArray;
If ([lineDic objectForKey: @ "eraseArray"]) {
EraseArray = [lineDic objectForKey: @ "eraseArray"];
} Else {
EraseArray = [NSMutableArray array];
}
[EraseArray addObject: [NSValue valueWithCGPoint: touchPoint];
[LineDic setObject: eraseArray forKey: @ "eraseArray"];
CGRect paintRect = CGRectMake (touchPoint. x-50, touchPoint. y-50, 100,100 );
[Self setNeedsDisplayInRect: paintRect];
// [Self setNeedsDisplay];
Continue;
}
}
}
}
// [Self eraseLine: currentLineDic erase: [thePan locationInView: self];
} Else {
If (thePan. state = UIGestureRecognizerStateBegan ){
NSMutableArray * currentLineArray = [NSMutableArray arrayWithObject: [NSValue valueWithCGPoint: touchPoint];
NSMutableDictionary * lineDic = [NSMutableDictionary dictionaryWithObjectsAndKeys: currentLineArray, @ "line", _ paintColor, @ "color", nil];
[LinesArray addObject: lineDic];
} Else if (thePan. state = UIGestureRecognizerStateChanged ){
NSMutableDictionary * lineDic = [linesArray lastObject];
NSMutableArray * currentLineArray = [lineDic objectForKey: @ "line"];
[CurrentLineArray addObject: [NSValue valueWithCGPoint: touchPoint];
CGRect paintRect = CGRectMake (touchPoint. x-50, touchPoint. y-50, 100,100 );
[Self setNeedsDisplayInRect: paintRect];
} Else if (thePan. state = UIGestureRecognizerStateEnded ){
 
}
}
}
@ End