The programm sets the background as an image through:
[backgroundViewProxy setBackgroundColor:[UIColor colorWithPatternImage:[theme backgroundImage]]];
The drawRect of the correspoinding UIView is:
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGSize phase = self.backgroundShift; //set this property to affect the positioning of the background image
CGContextSetPatternPhase(context, phase);
CGColorRef color = self.backgroundColor.CGColor;
CGContextSetFillColorWithColor(context, color);
CGContextFillRect(context, self.bounds);
CGContextRestoreGState(context);
}
I did not wrote the code on my own. I have to modify it.
I do understand what is going on here, but i cannot find a way to solve this problem:
I want the image to be centered on the screen (with and height) and it should not be streched or repeated.
At the moment, the image is repeated to fill the screen.
I have searched around the internet, but did not find a clear solution for centering(or positioning) the image in a similar context like this.
I would be glad if someone could help.
From apple's docs:
+ (UIColor *)colorWithPatternImage:(UIImage *)image
You can use pattern colors to set the fill or stroke color just as you would a solid color. During drawing, the image in the pattern color is tiled as necessary to cover the given area.
An alternative could be setting view.layer.contents to you image by casting it as type (id)
Related
I have an image of a my face and I just want to apply some filter or color on lips/eyes etc. I have detected the areas but my issue is how to add color there so that is looks natural and mix with existing image.
Please see the image below to have better idea what I need. See color applied on lips which is pretty much natural,
Use Following code to set any color to given filtered area. For Demo, I have used here rectangle to be get painted, you can use any other bounded area to fill up. Here i have used Yellow color to fill up, you can change that color too.
UIImage *image=...;//Add Code for getting Main Image
CGRect imageRect = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
UIGraphicsBeginImageContext(image.size);
[image drawInRect:imageRect];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(context, 1.0,1.0,0.0,0.5);//set RGBA for color to fill in given area
CGContextSetRGBStrokeColor(context, 1.0, 1.0, 0.0, 1.0);//set RGBA for Border color to add in given area
CGRect rect=CGRectMake(5,5,10,10);//Here, Use the area to be coloured, rightnow i have used Rectangle
CGContextFillRect(context,rect);
CGContextStrokeRectWithWidth(context, rect, 3);//Set Border Width in 3rd argument
CGContextSaveGState(context);
UIImage *newimage = UIGraphicsGetImageFromCurrentImageContext();
[UIImagePNGRepresentation(newimage) writeToFile:FileName] atomically:YES];
UIGraphicsEndImageContext();
There can be multiple ways to do this,one of them can be as mentioned in this link
The other approach can be u can create a UIView of the size same as size of your identified area,with whatever color you want and add that view as a subview on the face .
You can take the image and then apply a CoreImage filter to adjust the colors inside of a masked area that you've defined.
This answer outlines how to do this. Making it look natural more applies to just learning how to create filters that do what you want to the images.
You need to do some drawing customisation for particular image view. Here is some SO Q/A.
how to change the color of an individual pixel in uiimage
iPhone : How to change color of particular pixel of a UIImage?
The images that goes through here are PNGs of different shapes with a transparent background. In addition to merging them (which works fine), I'd like to give the new image a couple of pixels thick outline. But I can't seem to manage that.
(So just to clarify, I'm after an outline around the actual shapes in the context, not a rectangle around the entire image.)
+ (UIImage *)mergeBackgroundImage:(UIImage *)backgroundImage withOverlayingImage:(UIImage *)overlayImage{
UIGraphicsBeginImageContextWithOptions(backgroundImage.size, NO, backgroundImage.scale);
[backgroundImage drawInRect:CGRectMake(0, 0, backgroundImage.size.width, backgroundImage.size.height)];
[overlayImage drawInRect:CGRectMake(backgroundImage.size.width - overlayImage.size.width, backgroundImage.size.height - overlayImage.size.height, overlayImage.size.width, overlayImage.size.height)];
//Add stroke.
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return result;
}
Thanks for your time!
Markus
If you make a CALayer who's backing is set to a CGImage of your image, you can then use it as a masking layer for your layer that requires an outline1. And once you've done that, you can render your layer into another context, and then get another UIImage from that.
// edit: Something like what's describe in this answer.
I know similar question(s) have been asked before, but most answers say create a new detail disclosure button image with the required color (e.g. How to change color of detail disclosure button for table cell).
I want to be able to change it to any color I choose, dynamically, at run-time, so using a pre-configured image is not viable.
From reading around, I think there may be a few ways to do this, but I'm not sure which is the best, or exactly how to do it:
Draw the required color circle in code and overlay with an image of shadow round outside of circle and arrow right (with clear alpha channel for rest, so drawn color circle is still visible)
Add image of shadow round outside of circle in UIImageView, and using as a mask, flood fill within this shadow circle, then overlay the arrow.
Add greyscale image, mask it with itself, and overlay the required color (e.g. http://coffeeshopped.com/2010/09/iphone-how-to-dynamically-color-a-uiimage), then overlay that with arrow image.
What is the best way, and does anyone have any code showing exactly how to do it ?
I use the following helper method to tint a grayscale image. It takes the grayscale image, the tint color, and an option mask image used to ensure the tint only happens in part of the grayscale image. This method also ensure the new image has the same (if any) resizable insets as the original image.
+ (UIImage *)tintImage:(UIImage *)baseImage withColor:(UIColor *)color mask:(UIImage *)maskImage {
UIGraphicsBeginImageContextWithOptions(baseImage.size, NO, baseImage.scale);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGRect area = CGRectMake(0, 0, baseImage.size.width, baseImage.size.height);
CGContextScaleCTM(ctx, 1, -1);
CGContextTranslateCTM(ctx, 0, -area.size.height);
CGContextSaveGState(ctx);
if (maskImage) {
CGContextClipToMask(ctx, area, maskImage.CGImage);
} else {
CGContextClipToMask(ctx, area, baseImage.CGImage);
}
[color set];
CGContextFillRect(ctx, area);
CGContextRestoreGState(ctx);
CGContextSetBlendMode(ctx, kCGBlendModeOverlay);
CGContextDrawImage(ctx, area, baseImage.CGImage);
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
if (!UIEdgeInsetsEqualToEdgeInsets(baseImage.capInsets, UIEdgeInsetsZero)) {
newImage = [newImage resizableImageWithCapInsets:baseImage.capInsets];
}
return newImage;
}
Here is the non-retina grayscale detail disclosure image:
Here is the retina version:
Here is the non-retina mask (between the quotes - it's mostly white):
""
And the retina mask (between the quotes:
""
Consider also using an icon font in a label instead of an image. Something like glyphicons. Then you can set the text colour to whatever you want. You also have good options for scaling. The cost is that you don't have quite such precise control in some cases but it should work well for your case.
I have a circle with a black outline, and a white fill that I need to programmatically make the white into another color (via a UIColor). I've tried a handful of other stackoverflow solutions but none of them seem to work correctly, either filling just the outside or an outline.
I have two ways I could do this but I am unsure of how I would get the right results:
Tint just the white color to whatever the UIColor should be,
or,
Make a UIImage from two circles, one being filled and one overlapping that with black.
If you decide to use two circles, one white and one black, then you may find this helpful. This method will tint a uiimage one for you but it addresses the problem of only tinting the opaque part, meaning it will only tint the circle if you provide a png with transparency around the circle. So instead of filling the entire 24x24 frame of the image it fills only the opaque parts. This isn't exactly your question but you'll probably come across this problem if you go with the second option you listed.
-(UIImage*)colorAnImage:(UIColor*)color :(UIImage*)image{
CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height);
UIGraphicsBeginImageContextWithOptions(rect.size, NO, image.scale);
CGContextRef c = UIGraphicsGetCurrentContext();
[image drawInRect:rect];
CGContextSetFillColorWithColor(c, [color CGColor]);
CGContextSetBlendMode(c, kCGBlendModeSourceAtop);
CGContextFillRect(c, rect);
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return result;
}
Extend a UIView and just implement the drawRect method. For example, this will draw a green circle with a black outline.
- (void)drawRect:(CGRect)rect {
[super drawRect:rect];
CGContextRef gc = UIGraphicsGetCurrentContext();
[[UIColor greenColor] setFill];
CGContextFillEllipseInRect(gc, CGRectMake(0,0,24,24));
[[UIColor blackColor] set];
CGContextStrokeEllipseInRect(gc, CGRectMake(0,0,24,24));
}
For such simple shapes, just use CoreGraphics to draw a square and a circle -- adding the ability to set the fill color in your implementation.
If it's just black and white - then altering the white to another color is not so difficult when you know the color representations. Unfortunately, this is more complex to write and execute so… my recommendation is to just go straight to CoreGraphics for the simple task you outlined (bad pun, sorry).
here's a quick demo:
static void InsetRect(CGRect* const pRect, const CGFloat pAmount) {
const CGFloat halfAmount = pAmount * 0.5f;
*pRect = CGRectMake(pRect->origin.x + halfAmount, pRect->origin.y + halfAmount, pRect->size.width - pAmount, pRect->size.height - pAmount);
}
static void DrawBorderedCircleWithWidthInContext(const CGRect pRect, const CGFloat pWidth, CGContextRef pContext) {
CGContextSetLineWidth(pContext, pWidth);
CGContextSetShouldAntialias(pContext, true);
CGRect r = pRect;
/* draw circle's border */
CGContextSetRGBStrokeColor(pContext, 0.8f, 0.7f, 0, 1);
InsetRect(&r, pWidth);
CGContextStrokeEllipseInRect(pContext, r);
/* draw circle's fill */
CGContextSetRGBFillColor(pContext, 0, 0, 0.3f, 1);
InsetRect(&r, pWidth);
CGContextFillEllipseInRect(pContext, r);
}
I want to capture screen of my view from my iPhone app. I have white background view and on that I draw a lines on that view's layer using this method .
- (void)draw {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
if (self.fillColor) {
[self.fillColor setFill];
[self.path fill];
}
if (self.strokeColor) {
[self.strokeColor setStroke];
[self.path stroke];
}
CGContextRestoreGState(context);
}
- (void)drawRect:(CGRect)rect {
// Drawing code.
for (<Drawable> d in drawables) {
[d draw];
}
[delegate drawTemporary];
}
I have use delegate methods to draw lines on layer.
This is the project link from where I get help for this.
https://github.com/search?q=dudel&type=Everything&repo=&langOverride=&start_value=1
Now when I use the following context methods to save the drawing only I successfully save it without that white background.
drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
But When I use the following method of Bezier Pathe I cannot save the drawing without its white background,It saves the whole screen i.e. that drawing and its background.
UIGraphicsBeginImageContext(self.view.bounds.size);
[dudelView.layer renderInContext:UIGraphicsGetCurrentContext()];
//UIImage *finishedPic = UIGraphicsGetImageFromCurrentImageContext();
So can anybody help me how can I save the drawing only here in this app.
(You've tagged this as MapKit related, but make no mention of MapKit.)
Why don't you just split your drawing sequence into three chunks?
Draw your paths into an image context and get a UIImage, as you described.
Draw a background color.
Draw the UIImage.
Then you can use the UIImage for your "screenshot" as well.
I should also note that if the only thing you don't want in your captured UIImage is the background color, you are better off creating a UIImageView, setting its background color (-setBackgroundColor:), and setting its image to be your UIImage.
UIImageView internally has a number of optimizations that allow it to display graphics with much higher performance than you can get with a custom -drawRect: implementation.
Why don't you just save the drawables array? Those are all the drawings without the underlying image :)