In another post, luvieere shared a means by which rounded corners can be applied to a text view using the QuartzCore framework (see post). It would seem to me that a 3D border, like that found on a UITextField, could be created via layers instead of using a background image.
Does anyone know if or how this can be done? I'd really like to find a method to add a 3D border WITHOUT having to fire up a graphics editor and create a 3D shadowed background. Thanks!
In View Controller:
newCommentBody.layer.cornerRadius = 7;
newCommentBody.clipsToBounds = YES;
Make new class TextView inherits UITextView
#import "TextView.h"
#import <CoreGraphics/CoreGraphics.h>
#import <CoreGraphics/CGColor.h>
#implementation TextView
-(void) drawRect:(CGRect)rect {
UIGraphicsBeginImageContext(self.frame.size);
CGContextRef currentContext = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(currentContext, 1.0); //or whatever width you want
CGContextSetRGBStrokeColor(currentContext, 0.6, 0.6, .6, 1.0);
CGRect myRect = CGContextGetClipBoundingBox(currentContext);
//printf("rect = %f,%f,%f,%f\n", myRect.origin.x, myRect.origin.y, myRect.size.width, myRect.size.height);
float myShadowColorValues[] = {0,0,0,1};
CGColorSpaceRef myColorSpace = CGColorSpaceCreateDeviceRGB();
CGColorRef colorRef = CGColorCreate(myColorSpace, myShadowColorValues);
CGContextSetShadowWithColor(currentContext, CGSizeMake(0, -1), 3, colorRef);
// CGContextSetShadow(currentContext, CGSizeMake(0, -1), 3);
CGContextStrokeRect(currentContext, myRect);
UIImage *backgroundImage = (UIImage *)UIGraphicsGetImageFromCurrentImageContext();
UIImageView *myImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
[myImageView setImage:backgroundImage];
[self addSubview:myImageView];
[backgroundImage release];
UIGraphicsEndImageContext();
}
#end
m_txtViewSource.layer.borderWidth = 1;
m_txtViewSource.layer.borderColor = [[UIColor grayColor] CGColor];
it's not 3D but it simpler and safe code
Related
I want to make an effect like what you see on the right side of the first cell here:
I'm guessing it's some sort of overlay view with a gradient, but I just can't figure out how it's configured with transparency. I tried making my own overlay view with a gradient and set the alpha of the colors down, but it just shows up as a gray - white gradient.
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = UIGraphicsGetCurrentContext();
UIColor *gradBegin = [UIColor colorWithWhite:1.0 alpha:0.8];
UIColor *gradEnd = [UIColor colorWithWhite:1.0 alpha:0.6];
NSArray* gradientColors = [NSArray arrayWithObjects:
(id)gradBegin.CGColor,
(id)gradEnd.CGColor, nil];
CGFloat gradientLocations[] = {0, 1};
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef)gradientColors, gradientLocations);
CGContextDrawLinearGradient(context, gradient, CGPointMake(rect.origin.x, rect.origin.y + rect.size.height/2.0),
CGPointMake(rect.origin.x + rect.size.width, rect.origin.y + rect.size.height/2.0), 0);
What exactly is going on in this screenshot, and how can I replicate it?
I wrote a simple UIView class that will draw itself faded. It is a basic UIView with the drawRect overrided:
- (void)drawRect:(CGRect)rect
{
CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = UIGraphicsGetCurrentContext();
UIColor* gradBegin = [UIColor colorWithWhite:1 alpha:0];
UIColor* gradEnd = [UIColor colorWithWhite:1 alpha:1];
NSArray* gradColours = [NSArray arrayWithObjects:
(id)gradBegin.CGColor,
(id)gradBegin.CGColor,
(id)gradEnd.CGColor,
(id)gradEnd.CGColor, nil];
CGFloat gradLocs[] = { 0, 0.5, 0.9, 1 };
CGGradientRef gradient = CGGradientCreateWithColors(colourSpace, (__bridge CFArrayRef)gradColours, gradLocs);
CGContextDrawLinearGradient(context, gradient, CGPointMake(0, 0), CGPointMake(self.frame.size.width, 0), 0);
CGGradientRelease(gradient);
CGColorSpaceRelease(colourSpace);
}
This works if overlayed over your view and the view's background is white.
While this certainly can be done with Core Graphics, it's infinitely easier to add a transparent PNG to your project with the appropriate width and 1 pixel height and then position a UIImageView in your table cell over the content to create this effect.
The gradient drawing code in your question looks ok, although I haven't tested it. I suggest setting gradBegin.alpha = 0 and gradEnd.alpha = 1. Also, the last line could be simplified:
CGContextDrawLinearGradient(context, gradient, rect.origin,
CGPointMake(CGRectGetMaxX(rect), rect.origin.y, 0);
And don't forget to CGGradientRelease(gradient).
Anyway, other than that, you need to set overlayView.opaque = NO.
I want to add outline on an image, do you have any idea?
Note: I don't need the border of imageview, not imageview.layer.borderColor nor image.layer.borderWidth;
Try this :
- (UIImage*)imageWithBorderFromImage:(UIImage*)source;
{
CGSize size = [source size];
UIGraphicsBeginImageContext(size);
CGRect rect = CGRectMake(0, 0, size.width, size.height);
[source drawInRect:rect blendMode:kCGBlendModeNormal alpha:1.0];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBStrokeColor(context, 1.0, 0.5, 1.0, 1.0);
CGContextStrokeRect(context, rect);
UIImage *testImg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return testImg;
}
source : http://www.icodesnip.com/snippet/objective-c/add-image-border-to-uiimage
This may not be a very clean way but may work and is simple.
//Make a UIView instance with required coords and size
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(...)];
//Set a backgroundColor, that will be the color of your border
view.backgroundColor = [UIColor ...];
// Make a UIImageView instance with the frame just leaving enough
// space around for the border.
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(...)];
imageView.image = yourImage;
// Add the imageView to the view.
[view addSubview:imageView];
[imageView release];
// Release view accordingly after adding to some other view.
The sizes of the view and imageView will what give your image a border.
eg. (0, 0, 10, 10) -> view frame
(1, 1, 8, 8) -> imageView frame
This will give border of "1" to the image.
I'm trying to add shadow to a UINavigationController. My have is based on NavController and i'm trying to add a shadow like in game centers. I have this so far. It works n a UINavigationnBar but i'm trying to get it to work throughout the entire app.
CGColorRef darkColor = [[UIColor blackColor] colorWithAlphaComponent:.5f].CGColor;
CGColorRef lightColor = [UIColor clearColor].CGColor;
CAGradientLayer *newShadow = [[[CAGradientLayer alloc] init] autorelease];
newShadow.frame = CGRectMake(0, 44, 320, 10);
newShadow.colors = [NSArray arrayWithObjects:(id)darkColor, (id)lightColor, nil];
CALayer *superlayer = self.newShadow.superlayer;
[self.newShadow removeFromSuperlayer];
[superlayer addSublayer:self.newShadow];
[self.navigationBar.layer addSublayer:superlayer];
It works directly on a UINavigationBar but applying to a NavigationController project it fails. It builds but won't add the shadow. Any ideas?
EDIT:
I have been trying different approaches to this. I successfully created the gradient by using a shape.
#implementation UINavigationBar (UINavigationBarCategory)
- (void)drawRect:(CGRect)rect {
UIImage *backgroundImage;
backgroundImage = [UIImage imageNamed:#"nav.png"];
[backgroundImage drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorSpaceRef myColorspace = CGColorSpaceCreateDeviceRGB();
size_t num_locations = 2;
CGFloat locations[2] = { 1.0, 0.0 };
CGFloat components[8] = { 1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.5 };
CGGradientRef myGradient = CGGradientCreateWithColorComponents(myColorspace, components, locations, num_locations);
CGPoint myStartPoint, myEndPoint;
myStartPoint.x = 0.0;
myStartPoint.y = 0.0;
myEndPoint.x = 0.0;
myEndPoint.y = 54.0;
CGContextDrawLinearGradient (context, myGradient, myStartPoint, myEndPoint, 1);
}
I can't get the gradient below the UINavigationBar and its overlaying the image. I can't seem to get this to work. What i'm trying to do is add the same shadow Game Center has. I have tried a few different ways. All I need to do here is get this to lie underneath the UINavigationBar allowing the image to be on top and have a little part of the shadow lie on top on the UITableView so when you scroll up its above the UITableView. If you fire up Game Center you'll see exactly what i'm talking about.
I believe you should add it to the
UINavigationController.view.layer
As the UINavigationController he is not a UIView child.
if already you did so, an other way to effect the navigationbar, consistently all over the app is to use the UINavigationBarCategory:
you sould pace this at the end of your delegate - after the #end
#implementation UINavigationBar (UINavigationBarCategory)
- (void)drawRect:(CGRect)rect {
//implement your design
}
#end
EDIT
in this link you can find basic info on how to draw the bar:
An iPhone Graphics Drawing Tutorial using Quartz 2D
and here you can find how to add a shadow:adding shadow with quartz 2d
Good luck
You could subclass UIView and use your existing code to draw the shadow by overriding -drawRect:. Then wherever its needed, create it and add it to the view of the navigation controller.
Consider this example
CGFloat screenWidth = [UIScreen mainScreen].applicationFrame.size.width;
ShadowView *shadowView = [[ShadowView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, screenWidth, 20.0f)];
[self.navigationController.view insertSubview:shadowView atIndex:0];
By adding it to the view of the navigationController at index 0, you're effectively overlaying it on top of whatever the view controller is displaying. You could further improve this by checking for the scale of the main screen to appropriately calculate the height of the shadow view so that it will appear correctly on all devices regardless of having a retina display.
2 things i want to do, which are related:
Show a block of any colour. So i could change that colour to something else at any time.
Tint a UIImage to be a different colour. An overlay of colour with alpha turned down could work here, but say it was an image which had a transparent background and didn't take up the full square of the image.
Any ideas?
Another option, would be to use category methods on UIImage like this...
// Tint the image, default to half transparency if given an opaque colour.
- (UIImage *)imageWithTint:(UIColor *)tintColor {
CGFloat white, alpha;
[tintColor getWhite:&white alpha:&alpha];
return [self imageWithTint:tintColor alpha:(alpha == 1.0 ? 0.5f : alpha)];
}
// Tint the image
- (UIImage *)imageWithTint:(UIColor *)tintColor alpha:(CGFloat)alpha {
// Begin drawing
CGRect aRect = CGRectMake(0.f, 0.f, self.size.width, self.size.height);
UIGraphicsBeginImageContext(aRect.size);
// Get the graphic context
CGContextRef c = UIGraphicsGetCurrentContext();
// Converting a UIImage to a CGImage flips the image,
// so apply a upside-down translation
CGContextTranslateCTM(c, 0, self.size.height);
CGContextScaleCTM(c, 1.0, -1.0);
// Draw the image
[self drawInRect:aRect];
// Set the fill color space
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextSetFillColorSpace(c, colorSpace);
// Set the mask to only tint non-transparent pixels
CGContextClipToMask(c, aRect, self.CGImage);
// Set the fill color
CGContextSetFillColorWithColor(c, [tintColor colorWithAlphaComponent:alpha].CGColor);
UIRectFillUsingBlendMode(aRect, kCGBlendModeColor);
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// Release memory
CGColorSpaceRelease(colorSpace);
return img;
}
The first one is easy. Make a new UIView and set its background color to whatever color you’d like.
The second is more difficult. As you mentioned, you can put a new view on top of it with transparency turned down, but to get it to clip in the same places, you’d want to use a mask. Something like this:
UIImage *myImage = [UIImage imageNamed:#"foo.png"];
UIImageView *originalImageView = [[UIImageView alloc] initWithImage:myImage];
[originalImageView setFrame:CGRectMake(0.0f, 0.0f, 100.0f, 100.0f)];
[parentView addSubview:originalImageView];
UIView *overlay = [[UIView alloc] initWithFrame:[originalImageView frame]];
UIImageView *maskImageView = [[UIImageView alloc] initWithImage:myImage];
[maskImageView setFrame:[overlay bounds]];
[[overlay layer] setMask:[maskImageView layer]];
[overlay setBackgroundColor:[UIColor redColor]];
[parentView addSubview:overlay];
Keep in mind you’ll have to #import <QuartzCore/QuartzCore.h> in the implementation file.
Here is another way to implement image tinting, especially if you are already using QuartzCore for something else.
Import QuartzCore:
#import <QuartzCore/QuartzCore.h>
Create transparent CALayer and add it as a sublayer for the image you want to tint:
CALayer *sublayer = [CALayer layer];
[sublayer setBackgroundColor:[UIColor whiteColor].CGColor];
[sublayer setOpacity:0.3];
[sublayer setFrame:toBeTintedImage.frame];
[toBeTintedImage.layer addSublayer:sublayer];
Add QuartzCore to your projects Framework list (if it isn't already there), otherwise you'll get compiler errors like this:
Undefined symbols for architecture i386: "_OBJC_CLASS_$_CALayer"
An easy way to achieve 1 is to create a UILabel or even a UIView and change the backgroundColor as you like.
There is a way to multiply colours instead of just overlaying them, and that should work for 2. See this tutorial.
Try this
- (void)viewDidLoad
{
[super viewDidLoad];
UIView* maskedView = [self filledViewForPNG:[UIImage imageNamed:#"mask_effect.png"]
mask:[UIImage imageNamed:#"mask_image.png"]
maskColor:[UIColor colorWithRed:.6 green:.2 blue:.7 alpha:1]];
[self.view addSubview:maskedView];
}
-(UIView*)filledViewForPNG:(UIImage*)image mask:(UIImage*)maskImage maskColor:(UIColor*)maskColor
{
UIImageView *pngImageView = [[UIImageView alloc] initWithImage:image];
UIImageView *maskImageView = [[UIImageView alloc] initWithImage:maskImage];
CGRect bounds;
if (image) {
bounds = pngImageView.bounds;
}
else
{
bounds = maskImageView.bounds;
}
UIView* parentView = [[UIView alloc]initWithFrame:bounds];
[parentView setAutoresizesSubviews:YES];
[parentView setClipsToBounds:YES];
UIView *overlay = [[UIView alloc] initWithFrame:bounds];
[[overlay layer] setMask:[maskImageView layer]];
[overlay setBackgroundColor:maskColor];
[parentView addSubview:overlay];
[parentView addSubview:pngImageView];
return parentView;
}
I am having a lot of trouble trying to find out how to draw a transparent circle on top of a UIImage within my UIImageView. Google-ing gives me clues, but I still can't find a working example.
Are there any examples that anyone knows of that demonstrate this?
Easiest way is simply to create a semi-transparent square UIView, then set the cornerRadius of its layer to be half of its width/height. Something like:
UIView *squareView = [[UIView alloc] initWithFrame:CGRectMake(0,0,100,100)];
squareView.alpha = 0.5;
squareView.layer.cornerRadius = 50;
...
[squareView release];
This has got to be the simplest solution:
CGFloat r = 150;
UILabel *lbl = [[UILabel alloc] initWithFrame:CGRectMake(0,0,1.5*r,1.5*r)];
lbl.text = #"●";
lbl.transform = CGAffineTransformMakeTranslation(0.0f, -r/6);
lbl.textAlignment = UITextAlignmentCenter;
lbl.backgroundColor = [UIColor clearColor];
lbl.textColor = [UIColor redColor];
lbl.font = [UIFont systemFontOfSize:2*r];
lbl.alpha = 0.5;
lbl.center = self.view.center;
[self.view addSubview:lbl];
One way would be to add a CAShapeLayer with a circular path, either directly to the layer of the UIImageView or as the layer of a new UIView that is added to the UIImageView.
If you actually want to modify the image, then create a mutable copy of it by drawing it into a CGBitmapContext then creating a new image from the modified bitmap.
CGPathRef circlePath = CGPathCreateMutable();
CGPathAddEllipseInRect( circlePath , NULL , CGRectMake( 0,0,20,20 ) );
CAShapeLayer *circle = [[CAShapeLayer alloc] init];
circle.path = circlePath;
circle.opacity = 0.5;
[myImageView.layer addSublayer:circle];
CGPathRelease( circlePath );
[circle release];
You can implement a custom sub-class of UIView that draws your image and then the circle in the drawRect method:
#interface CircleImageView : UIView {
UIImage * m_image;
CGRect m_viewRect;
// anything else you need in this view?
}
Implementation of drawRect:
- (void)drawRect:(CGRect)rect {
// first draw the image
[m_image drawInRect:m_viewRect blendMode:kCGBlendModeNormal alpha:1.0];
// then use quartz to draw the circle
CGContextRef context = UIGraphicsGetCurrentContext ()
// stroke and fill black with a 0.5 alpha
CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 0.5);
CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 0.5);
// now draw the circle
CGContextFillEllipseInRect (context, m_viewRect);
}
You will need to set up the m_viewRect and m_image member functions on init.