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MainView.m
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MainView.m
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//
// MainView.m
// Painter
//
// Created by Edward Chiang on 2010/12/10.
// Copyright 2010 Edward in Action. All rights reserved.
//
#import "MainView.h"
@implementation MainView
@synthesize color;
@synthesize lineWidth;
- (id) initWithCoder:(NSCoder *)aDecoder {
if (self = [super initWithCoder:aDecoder]) {
// initialize squiggles and finishedSquiggles
squiggles = [[NSMutableDictionary alloc] init];
finishedSquiggles = [[NSMutableArray alloc] init];
// the starting color is black
color = [[UIColor alloc] initWithRed:0 green:0 blue:0 alpha:1];
lineWidth = 5;
}
return self;
}
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
// Initialization code.
}
return self;
}
// 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();
for (Squiggle *squiggle in finishedSquiggles)
[self drawSquiggle:squiggle inContext:context];
for (NSString *key in squiggles) {
Squiggle *squiggle = [squiggles valueForKey:key];
[self drawSquiggle:squiggle inContext:context];
}
}
// draws the given squiggle into the given context
- (void)drawSquiggle:(Squiggle *)squiggle inContext:(CGContextRef)context {
// set the drawing color to the squiggle's color
UIColor *squiggleColor = squiggle.strokeColor;
CGColorRef colorRef = [squiggleColor CGColor]; // get the CGColor
CGContextSetStrokeColorWithColor(context, colorRef);
// set the line width to the squiggle's line width
CGContextSetLineWidth(context, squiggle.lineWidth);
NSMutableArray *points = [ squiggle points]; // get points from squiggle
// retrieve the NSValue object and store the value in firstPoint
CGPoint firstPoint; // declare a CGPoint
[[points objectAtIndex:0] getValue:&firstPoint];
// move to the point
CGContextMoveToPoint(context, firstPoint.x, firstPoint.y);
// draw a line from each point to the next in order
for (int i=1; i < [points count]; i++) {
NSValue *value = [points objectAtIndex:i];
CGPoint point; // declare a new point
[value getValue:&point]; // store the value in point
// draw a line to the new point
CGContextAddLineToPoint(context, point.x, point.y);
} // end for
CGContextStrokePath(context);
UIGraphicsPushContext(context);
}
// called when the user lefts a finger from the screen
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
// loop through the touches
for (UITouch *touch in touches) {
// get the unique key for the touch
NSValue *touchValue = [NSValue valueWithPointer:touch];
NSString *key = [NSString stringWithFormat:@"%@", touchValue];
// retrieve the squiggle for this touch using the key
Squiggle *squiggle = [squiggles valueForKey:key];
// remove the squiggle from the dictionary and place it in an array // of finished squiggles [finishedSquiggles addObject:squiggle]; // add to finishedSquiggles [squiggles removeObjectForKey:key]; // remove from squiggles
[finishedSquiggles addObject:squiggle]; // add to finishedSquiggles
[squiggles removeObjectForKey:key]; // remove from squiggles
}//endfor
}
// clear the painting if the user touched the "Clear" button
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
// if the user touched the Clear button
if (buttonIndex ==1 )
[self resetView]; // clear the screen
}
// determines if this view can become the first responder
- (BOOL)canBecomeFirstResponder {
return YES;
}
// called when a motion event, such as a shake, ends
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
// if a shake event ended
if (event.subtype == UIEventSubtypeMotionShake){
// create an alert prompting the user about clearing the painting
NSString *message = @"Are you sure you want to clear the painting?";
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Clear painting" message:message delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"clear", nil];
[alert show];
[alert release];
}// end if
[super motionEnded:motion withEvent:event];
} // end method
// called whenever the user places a finger on the screen
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSArray *array = [ touches allObjects]; // get all the new touches
// loop through each new touch
for (UITouch *touch in array ) {
// create and configure a new squiggle
Squiggle *squiggle = [[Squiggle alloc] init];
[squiggle setStrokeColor:color]; // set squiggle's stroke color
[squiggle setLineWidth:lineWidth]; // set squiggle's line width
// add the location of the first touch to the squiggle
//[squiggle addPoint:[touch locationInView:self]];
// the key for each touch is the value of the pointer
NSValue *touchValue = [NSValue valueWithPointer:touch];
NSString *key = [NSString stringWithFormat:@"%@", touchValue];
// add the new touch to the dictionary under a unique key
[squiggles setValue:squiggle forKey:key];
[squiggle release]; // we are done with squiggle so release it
} // end for
}
// called whenever the user drags a finger on the screen
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
NSArray *array = [touches allObjects]; // get all the moved touches
// loop through all the touches
for (UITouch *touch in array) {
// get the unique key for this touch
NSValue * touchValue = [NSValue valueWithPointer:touch];
// fetch the squiggle this touch should be added to using the key
Squiggle *squiggle = [squiggles valueForKey:[NSString stringWithFormat:@"%@", touchValue]];
// get the current and previous touch locations
CGPoint current = [touch locationInView:self];
CGPoint previous = [touch previousLocationInView:self];
[squiggle addPoint:current]; // add the new point to the squiggle
// screen needs to be redrawn
CGPoint lower, higher;
lower.x = (previous.x > current.x ? current.x : previous.x);
lower.y = (previous.y > current.y ? current.y: previous.y);
higher.x = (previous.x < current.x ? current.x : previous.x);
higher.y = (previous.y < current.y ? current.y: previous.y);
// redraw the screen in the required region
[self setNeedsDisplayInRect:CGRectMake(lower.x - lineWidth,
lower.y - lineWidth, higher.x - lower.x + lineWidth * 2,
higher.y - lower.y + lineWidth * 2)];
} // end for
}
// clear the paintings in main view
- (void)resetView {
[squiggles removeAllObjects];
[finishedSquiggles removeAllObjects];
[self setNeedsDisplay]; // refresh the display
}
- (void)dealloc {
[squiggles release]; // release the squiggles NSMutableDictionary
[finishedSquiggles release]; // release finishedSquiggles
[color release]; // release the color UIColor
[super dealloc];
}
@end