Xcode 5
I am trying to create a custom cropping rectangle to crop image. FOr that I understand I need to override drawRect() method in a class extending UIView. But then I don't know how to use that class in ViewController to show it.
Please correct if I am going in wrong direction. I am a little new to this.
MDCustomCropRect.h
#import <UIKit/UIKit.h>
#interface MDCustomCropRect : UIView
#end
MDCustomCropRect.m
- (void)drawRect:(CGRect)rect
{
// Drawing code
CGRect rectangle = CGRectMake(0, 100, 320, 100);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 0.0); //this is the transparent color
CGContextSetRGBStrokeColor(context, 0.0, 0.0, 0.0, 0.5);
CGContextFillRect(context, rectangle);
CGContextStrokeRect(context, rectangle); //this will draw the border
}
In your viewController
MDCustomCropRect *myView = [[MDCustomCropRect alloc] init];
myView.frame = CGRectMake(10,10,200,100);
myView.backgroundColor = [UIColor greenColor];
[self.view addSubView:myView]
Just add your view as a subview of your UIViewController's view.
In your viewController code, typically in viewDidLoad method :
// create your view
MDCustomCropRect *myView = [[MDCustomCropRect alloc] init];
[self.view addSubView:myView]
// you can manually set your view frame - in this case use initWithFrame: instead of init
// OR use layout constraints : define and add constraints AFTER your inserted your view as a subview
EDIT:
In your case, as you're only drawing a rectangle - which is what UIView is - you could instead to the following :
UIView *myRectangleView = [[UIView alloc] initWithFrame:CGRectMake(0, 100, 320, 100)];
myRectangleView.backgroundColor = [UIColor clearColor];
myRectangleView.layer.borderWidth = 1;
myRectangleView.layer.borderColor = [UIColor colorWithWhite:0 alpha:0.5].CGColor;
[self.view addSubView:myRectangleView];
There is no need for a specific drawRect in your case
Related
Hi i want to create a quarter transparent hole at right bottom on overlay UIView.
i am able to solve it using below code. But it does not look right as i am creating a rectangle outside the bond of view.
What i have tried:
#implementation PartialTransparentView
- (id)initWithBottomRightCornerRadiusForView:(UIView *)view withRadius:(CGFloat)radius
{
[self commonInitWithRect:CGRectMake(view.frame.size.width - radius, view.frame.size.height - radius, radius*2, radius*2)];
self = [super initWithFrame:CGRectMake(0, 0, 5000, 5000)];//**it does not look right to me**
if (self) {
// Initialization code
self.opaque = NO;
}
return self;
}
-(void)commonInitWithRect:(CGRect)rect{
backgroundColor = [UIColor colorWithWhite:1 alpha:0.75];
rectToBeSurrounded = rect;
}
- (void)drawRect:(CGRect)rect {
[backgroundColor setFill];
UIRectFill(rect);
CGFloat x = rectToBeSurrounded.origin.x;
CGFloat y = rectToBeSurrounded.origin.y;
CGFloat width = rectToBeSurrounded.size.width;
CGFloat height = rectToBeSurrounded.size.height;
//create outer square
CGFloat outerX = (x - width/2);
CGFloat outerY = y - height/2;
CGFloat outerWidth = 2*width;
CGFloat outerHeight = outerWidth;
//create outer square
CGRect outerRect = CGRectMake(outerX, outerY, outerWidth, outerHeight);
CGRect holeRectIntersection = CGRectIntersection( outerRect, rect );
CGContextRef context = UIGraphicsGetCurrentContext();
if( CGRectIntersectsRect( holeRectIntersection, rect ) )
{
CGContextAddEllipseInRect(context, holeRectIntersection);
CGContextClip(context);
CGContextClearRect(context, holeRectIntersection);
CGContextSetFillColorWithColor( context, [UIColor clearColor].CGColor );
CGContextFillRect( context, holeRectIntersection);
}
}
Now i am using above code as :
PartialTransparentView *transparentView = [[PartialTransparentView alloc] initWithBottomRightCornerRadiusForView:self.view withRadius:50];
[self.view addSubview:transparentView];
Result as expected:
i know my solution will break if i have to acheive same thing but on top left of view.
what i am looking for just provide center (x, y) and radius for circle and get desired results.
Thanks
Basd on Mr.T
UIView *transparentView = [[UIView alloc] initWithFrame:self.view.frame];
[transparentView setBackgroundColor:[UIColor colorWithWhite:1 alpha:0.75]];
[self.view addSubview:transparentView];
circleView *acircleView = [[circleView alloc] initWithFrame:CGRectMake(50, 50, 60, 60)];
[acircleView setBackgroundColor:[UIColor grayColor]];
[transparentView addSubview:acircleView];
and circleView.m
- (void)drawRect:(CGRect)rect {
// Drawing code
//// Oval Drawing
UIBezierPath* ovalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(50, 50, 60, 60)];
[UIColor.grayColor setFill];
[ovalPath fill];
}
output:
My suggestions is to add the transparent view as a separate view on your view controller. This can be either done on storyboard,so that you can set the background color and the alpha value to give the transparent effect!!!
Now create another view to make the circle and add it to transparent view, , and move this view on the transparent view according to your need!!!
Create the circle using bezier path:
circleView.m
- (void)drawRect:(CGRect)frame {
//// Oval Drawing
UIBezierPath* ovalPath = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(CGRectGetMinX(frame), CGRectGetMinY(frame), 60, 60)];
[UIColor.grayColor setFill];
[ovalPath fill];
}
For testing purpose, I have created a circle view on my IB and created an outlet property in my view controller.
HEre is the screenshot.
Now to move the circle, I can simply change the frame of the circle view, wherever I need.
For example, If I want to move it to top left, I simply do:
-(void)moveCircleViewwithX:(float) x withY:(float) y{
_cView.frame=CGRectMake(x, y, _cView.frame.size.width, _cView.frame.size.height);
}
The result will be:
Update
Put the following the drawRect method of transparentView:
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGRect transparentPart = self.seeRect; //this is the rect of the circle view
CGContextAddEllipseInRect(ctx,transparentPart); //make the circle shape
CGContextClip(ctx);
CGContextClearRect(ctx, transparentPart);
and in your view controller:
when you want to apply the mask i.e the transparent for both circle and for the transparent layer:
-(void)applyMask{
[_cView setCircleColor:[UIColor clearColor]]; //circle view bezier path color
[_cView setNeedsDisplay];
[_tView setSeeRect:_cView.frame]; //set the transparency cut on transparency view
[_tView setNeedsDisplay];
}
Once you do this, you will get the transparency view!!!
You can move the circle by simply calling
[self moveCircleViewwithX:-30 withY:10]; //top left corner
and you can apply the transparency mask by simply calling:
[self applyMask];
So, the final result after you call the applyMask method will be:
I have a label in my view. Now I want to draw a line above the label, which means you can see the label is under the line.
So far I can draw a line using quartz2D but always under the label. Is there any way to solve my problems?
You can create a CAShapeLayer like this:
CAShapeLayer *lineLayer = [CAShapeLayer layer];
lineLayer.frame = self.label.bounds;
lineLayer.strokeColor = [UIColor redColor].CGColor;
CGRect rect = CGRectMake(0, CGRectGetMidY(lineLayer.bounds), lineLayer.bounds.size.width, 2);
lineLayer.path = [UIBezierPath bezierPathWithRect:rect].CGPath;
And then add it to the UILabel like this:
[self.label.layer addSublayer:lineLayer];
To be honest, the easiest thing to do is to create a 2x2 pixel image called line#2x.png, and have the bottom 2 pixels black, the top 2 transparent, then use it as the background image for an image view. Stretch the image view to whatever width you need by using it as a pattern image. The 1x image should be a 1x1px, all black.
UIView *lineView = [[UIView alloc] initWithFrame:frame]; // Whatever frame the line needs
// Add the line image as a pattern
UIColor *patternColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"line.png"]];
lineView.backgroundColor = patternColor;
[self.view addSubview:lineView];
If this is a label you will be using a lot, you could make a sub-class of UILabel and override the drawRect function.
- (void) drawRect:(CGRect)r
{
[super drawRect:r];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
CGContextSetLineWidth(context, 1.0);
CGContextMoveToPoint(context, 1.0, 1.0);
CGContextAddLineToPoint(context, self.bounds.size.width - 1.0, 1.0);
CGContextStrokePath(context);
CGContextRestoreGState(context);
}
The advantage here is that the line will be "baked" into the view and only be draw once. Other methods such as CAShapeLayer or UIView will be re-rendered every frame.
For bonus points, you can make the color and line width properties :)
I'm trying to draw a straight dashed line. I've gotten it so it draws the dashes, but this black background color remains. I've seem many answers to other questions, but none of them worked.
Apple's documentation seems to point to the fill color and using either CGContextFillPath or CGContextDrawPath, but neither of those work and the background of the dashed line is still black.
- (void)drawRect:(CGRect)rect {
CGContextRef contextRef = UIGraphicsGetCurrentContext();
GLFloat lines[] = {self.frame.size.width, self.frame.size.width*2};
CGFloat grey[4] = {0.6f, 0.6f, 0.6f, 1.0f};
CGContextSetStrokeColor(contextRef, grey);
CGContextSetFillColorWithColor(contextRef, [[UIColor clearColor] CGColor]);
CGContextSetLineDash(contextRef, 0, lines, 2);
CGContextSetLineWidth(contextRef, self.frame.size.width);
CGContextBeginPath(contextRef);
CGContextMoveToPoint(contextRef, 0, 0);
CGContextAddLineToPoint(contextRef, 0, self.frame.size.height);
CGContextDrawPath(contextRef, kCGPathFillStroke);
}
When manually adding this view to your view hierarchy, you just have to make sure you're setting the background color. For example, if you're initializing your view with initWithFrame, then set the background color in that method:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self setBackgroundColor:[UIColor clearColor]];
}
return self;
}
Or, alternatively, when adding the view, set the background color there:
CustomView *customView = [[CustomView alloc] initWithFrame:frame];
customView.backgroundColor = [UIColor clearColor];
[self.view addSubview:customView];
I want to add a border in a CGRect. Although previous solutions suggest either this:
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(context, 1.0, 0.0, 0.0, 1.0);
CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0);
CGContextFillRect(context, rectangle);
or something like this:
view.layer.borderWidth = 10;
view.layer.borderColor = [UIColor redColor].CGColor;
I cannot apply either of this in my approach.
In my mainView Controller I am having this code:
-(void)actionHint
{
CGRect viewRect = CGRectMake(kScreenWidth/2 -kMenuWidth, kScreenHeight/2-kMenuHeight - 70,kMenuWidth*10, kMenuHeight*4);
HintMenu* hintMenu = [HintMenu viewWithRect:viewRect];
[hintMenu.btnReveal addTarget:self action:#selector(actionReveal) forControlEvents:UIControlEventTouchUpInside];
[hintMenu.btnNewAnag addTarget:self action:#selector(actionNewAnagram) forControlEvents:UIControlEventTouchUpInside];
[self.gameView addSubview:hintMenu];
}
I am creating a game and I want a simple rect with some help actions to come on top of my current view. The code for viewRect is:
+(instancetype)viewWithRect:(CGRect)r
{
HintMenu* hint = [[HintMenu alloc] initWithFrame:r];
hint.userInteractionEnabled = YES;
UIImage* image=[UIImage imageNamed:#"btn"];
... rest of items in the cgrect
return hint;
}
Where should I add the code for adding the borders and what that code should be?
Your HintMenu is a type of view so in its initWithFrame method you can do:
self.layer.borderWidth = 10;
self.layer.borderColor = [UIColor redColor].CGColor;
You can use this code to create a bordered rectangle. All you have to do is import the QuartzCore framework. Feel free to copy+paste this code.
#import <QuartzCore/QuartzCore.h>
-(void)viewDidLoad{
//give it a blue background
self.layer.backgroundColor=[UIColor blueColor].CGColor;
//set the boarder width
self.layer.borderWidth=5;
//set the boarder color
self.layer.borderColor=[UIColor redColor].CGColor;
}
I am having a UIView which contains other subviews. I am applying border to this UIView and the border is applied to the whole UIView. For that see the first image.
But do not want the border around the title where it says "Leaderboard". How can i remove the border for that portion only. See the below image and in that see that there is no border around the header Leaderboard..
NO,CALayer borders don’t support that behavior.
But you can try an alternate method if you need to implement this,
try adding an n-point-wide opaque subview with your desired border color as its background color, on each side of your main view.
Add this Code:
CGSize mainViewSize = theView.bounds.size;
CGFloat borderWidth = 2;
UIColor *borderColor = [UIColor redColor];
CGFloat heightfromTop = 25;
UIView *leftView = [[UIView alloc] initWithFrame:CGRectMake(0, heightfromTop borderWidth, mainViewSize.height-heightfromTop)];
UIView *rightView = [[UIView alloc] initWithFrame:CGRectMake(mainViewSize.width - borderWidth, heightfromTop, borderWidth, mainViewSize.height-heightfromTop)];
leftView.opaque = YES;
rightView.opaque = YES;
leftView.backgroundColor = borderColor;
rightView.backgroundColor = borderColor;
[mainView addSubview:leftView];
[mainView addSubview:rightView];
This will add borders to both sides only.Repeat the same idea for top and bottom also.
NB : heightfromTop is the height of the top section where you don't want the border view to be present, you can alter it as per your needs
You can subclass the UIView and implement the drawRect like:
- (void)drawRect:(CGRect)rect
{
float borderSize = 3.0f;
//draw the bottom border
CGContextSetFillColorWithColor(context, [UIColor blueColor].CGColor);
CGContextFillRect(context, CGRectMake(0.0f, self.frame.size.height - borderSize, self.frame.size.width, borderSize));
//draw the right border
CGContextSetFillColorWithColor(context, [UIColor blueColor].CGColor);
CGContextFillRect(context, CGRectMake(0.0f,0.0f, borderSize,self.frame.size.height));
//draw the left border
CGContextSetFillColorWithColor(context, [UIColor blueColor].CGColor);
CGContextFillRect(context, CGRectMake(self.frame.size.width - borderSize,0.0f, borderSize,self.frame.size.height));
}
Now, you need to use the subclassed UIView for creating the needed view.