iPhone paint bucket - iphone

Question

I am working on implementing a flood-fill paint-bucket tool in an iPhone app and am having some trouble with it. The user is able to draw and I would like the paint bucket to allow them to tap a spot and fill everything of that color that is connected.
Here's my idea:
1) Start at the point the user selects
2) Save points checked to a NSMutableArray so they don't get re-checked
3) If the pixel color at the current point is the same as the original clicked point, save to an array to be changed later
4) If the pixel color at the current point is different than the original, return. (boundary)
5) Once finished scanning, go through the array of pixels to change and set them to the new color.
But this is not working out so far. Any help or knowledge of how to do this would be greatly appreciated! Here is my code.
-(void)flood:(int)x:(int)y
{
//NSLog(#"Flood %i %i", x, y);
CGPoint point = CGPointMake(x, y);
NSValue *value = [NSValue valueWithCGPoint:point];
//Don't repeat checked pixels
if([self.checkedFloodPixels containsObject:value])
{
return;
}
else
{
//If not checked, mark as checked
[self.checkedFloodPixels addObject:value];
//Make sure in bounds
if([self isOutOfBounds:x:y] || [self reachedStopColor:x:y])
{
return;
}
//Go to adjacent points
[self flood:x+1:y];
[self flood:x-1:y];
[self flood:x:y+1];
[self flood:x:y-1];
}
}
- (BOOL)isOutOfBounds:(int)x:(int)y
{
BOOL outOfBounds;
if(y > self.drawImage.frame.origin.y && y < (self.drawImage.frame.origin.y + self.drawImage.frame.size.height))
{
if(x > self.drawImage.frame.origin.x && x < (self.drawImage.frame.origin.x + self.drawImage.frame.size.width))
{
outOfBounds = NO;
}
else
{
outOfBounds = YES;
}
}
else
{
outOfBounds = YES;
}
if(outOfBounds)
NSLog(#"Out of bounds");
return outOfBounds;
}
- (BOOL)reachedStopColor:(int)x:(int)y
{
CFDataRef theData = CGDataProviderCopyData(CGImageGetDataProvider(self.drawImage.image.CGImage));
const UInt8 *pixelData = CFDataGetBytePtr(theData);
int red = 0;
int green = 1;
int blue = 2;
//RGB for point being checked
float newPointR;
float newPointG;
float newPointB;
//RGB for point initially clicked
float oldPointR;
float oldPointG;
float oldPointB;
int index;
BOOL reachedStopColor = NO;
//Format oldPoint RBG - pixels are every 4 bytes so round to 4
index = lastPoint.x * lastPoint.y;
if(index % 4 != 0)
{
index -= 2;
index /= 4;
index *= 4;
}
//Get into 0.0 - 1.0 value
oldPointR = pixelData[index + red];
oldPointG = pixelData[index + green];
oldPointB = pixelData[index + blue];
oldPointR /= 255.0;
oldPointG /= 255.0;
oldPointB /= 255.0;
oldPointR *= 1000;
oldPointG *= 1000;
oldPointB *= 1000;
int oldR = oldPointR;
int oldG = oldPointG;
int oldB = oldPointB;
oldPointR = oldR / 1000.0;
oldPointG = oldG / 1000.0;
oldPointB = oldB / 1000.0;
//Format newPoint RBG
index = x*y;
if(index % 4 != 0)
{
index -= 2;
index /= 4;
index *= 4;
}
newPointR = pixelData[index + red];
newPointG = pixelData[index + green];
newPointB = pixelData[index + blue];
newPointR /= 255.0;
newPointG /= 255.0;
newPointB /= 255.0;
newPointR *= 1000;
newPointG *= 1000;
newPointB *= 1000;
int newR = newPointR;
int newG = newPointG;
int newB = newPointB;
newPointR = newR / 1000.0;
newPointG = newG / 1000.0;
newPointB = newB / 1000.0;
//Check if different color
if(newPointR < (oldPointR - 0.02f) || newPointR > (oldPointR + 0.02f))
{
if(newPointG < (oldPointG - 0.02f) || newPointG > (oldPointG + 0.02f))
{
if(newPointB < (oldPointB - 0.02f) || newPointB > (oldPointB + 0.02f))
{
reachedStopColor = YES;
NSLog(#"Different Color");
}
else
{
NSLog(#"Same Color3");
NSNumber *num = [NSNumber numberWithInt:index];
[self.pixelsToChange addObject:num];
}
}
else
{
NSLog(#"Same Color2");
NSNumber *num = [NSNumber numberWithInt:index];
[self.pixelsToChange addObject:num];
}
}
else
{
NSLog(#"Same Color1");
NSNumber *num = [NSNumber numberWithInt:index];
[self.pixelsToChange addObject:num];
}
CFRelease(theData);
if(reachedStopColor)
NSLog(#"Reached stop color");
return reachedStopColor;
}
-(void)fillAll
{
CGContextRef ctx;
CGImageRef imageRef = self.drawImage.image.CGImage;
NSUInteger width = CGImageGetWidth(imageRef);
NSUInteger height = CGImageGetHeight(imageRef);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
unsigned char *rawData = malloc(height * width * 4);
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
CGContextRef context = CGBitmapContextCreate(rawData, width, height,
bitsPerComponent, bytesPerRow, colorSpace,
kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
CGContextRelease(context);
int red = 0;
int green = 1;
int blue = 2;
int index;
NSNumber *num;
for(int i = 0; i < [self.pixelsToChange count]; i++)
{
num = [self.pixelsToChange objectAtIndex:i];
index = [num intValue];
rawData[index + red] = (char)[[GameManager sharedManager] RValue];
rawData[index + green] = (char)[[GameManager sharedManager] GValue];
rawData[index + blue] = (char)[[GameManager sharedManager] BValue];
}
ctx = CGBitmapContextCreate(rawData,
CGImageGetWidth( imageRef ),
CGImageGetHeight( imageRef ),
8,
CGImageGetBytesPerRow( imageRef ),
CGImageGetColorSpace( imageRef ),
kCGImageAlphaPremultipliedLast );
imageRef = CGBitmapContextCreateImage (ctx);
UIImage* rawImage = [UIImage imageWithCGImage:imageRef];
CGContextRelease(ctx);
self.drawImage.image = rawImage;
free(rawData);
}

Answer 1

so i found this (i know the question might be irrelevant now but for people who are still looking for something like this it's not ) :
to get color at pixel from context (modified code from here) :
- (UIColor*) getPixelColorAtLocation:(CGPoint)point {
UIColor* color;
CGContextRef cgctx = UIGraphicsGetCurrentContext();
unsigned char* data = CGBitmapContextGetData (cgctx);
if (data != NULL) {
int offset = 4*((ContextWidth*round(point.y))+round(point.x)); //i dont know how to get ContextWidth from current context so i have it as a instance variable in my code
int alpha = data[offset];
int red = data[offset+1];
int green = data[offset+2];
int blue = data[offset+3];
color = [UIColor colorWithRed:(red/255.0f) green:(green/255.0f) blue:(blue/255.0f) alpha:(alpha/255.0f)];
}
if (data) { free(data); }
return color;
}
and the fill algorithm: is here
This is what i'm using but the fill itself is quite slow compared to CGPath drawing styles. Tho if you're rendering offscreen and/or you fill it dynamically like this it looks kinda cool :