In Android I can draw lines by simple creating a view and setting its background color
<LinearLayout...>
...
<View android:layout_width="1dp"
android:layout_height="match_parent"
android:background="#color/black"
...
<View android:layout_width="match_parent"
android:layout_height="2dp"
android:background="#color/red"
...
</LinearLayout>
This is a common practice in Android. How might I do the same in iOS? What's the common practice? I see another question here trying to ask a similar question but was told to use a TableView. I am looking for something as simple and as general as the Android answer.
You can create a generic UIView and set its width or height to 1 pt in a storyboard. Set its backgroundColor to what you want the line to be. Make sure you set its constraints or resizing mask so that it doesn't grow in width/height when the screen is resized.
UIView *lineView = [[UIView alloc]init];
lineView.frame = CGRectMake(0,50,self.View.frame.size.width,1);
lineView.backgroundColor = [UIColor blackColor];
[self.view addSubview:lineView];
Take this simple view created in code and just adjust its height by 1 or 2
Just like in the above code -> lineView.frame =CGRectMake(<#CGFloat x#>, <#CGFloat y#>, <#CGFloat width#>, <#CGFloat height#>);
CGFloat height is taken is 1
The same exact thing. Use a UIView with a small width and set its background color to the desired color.
// to draw line in uiview class
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 1.0);
CGContextSetStrokeColorWithColor(context, [[UIColor whiteColor] CGColor]);
CGContextMoveToPoint(context, xstartPoint, yStart);
CGContextAddLineToPoint(context, xstartPoint, yBottom);
CGContextStrokePath(context);
CGContextSaveGState(context);
Related
I’m trying to make a custom UIProgressView where the image that gets filled up is the Nike Swoosh. I’ve tried to follow some tutorials but am getting nowhere.
My current approach:
Make the inside of swoosh transparent and surroundings black.
Then put a big UIProgressView behind that.
Since the middle of the swoosh is transparent, it looks like the swoosh is filling up.
But, modifying the height of the progress bar has proven to be a pain since it messes with the width in a weird way…and it’s hard to align the swoosh with the progress bar for responsiveness.
Are there any other ideas or libraries out there?
Thanks
My suggestion:
draw a second image programatically to apply as a mask against your 'swoosh' image, and then repeat this cyclically.
example, fill image from left (mask it from right)
{
//existing variables
IBOutlet UIImageView *swooshView;
}
-(UIImage *)maskImageOfSize:(CGSize )size filledTo:(CGFloat )percentage{
UIGraphicsBeginImageContextWithOptions ( size, NO, 0.0);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColourWithColour (context, [UIColor blackColor].CGColor);
CGRect fillRect = CGRectZero;
fillRect.size.height = size.height;
fillRect.size.width = size.width * percentage / 100.0;
fillRect.origin.x = (size.width - fillRect.size.width);
CGContextFillRect(context, fillRect);
UIImage *result = UIGraphicsGetImageFromImageContext();
UIGraphicsEndImageContext();
return result;
}
-(void)fillSwooshToPercentage:(CGFloat )percentage{
percentage = ((CGFloat ) fmaxf ( 0.0 , (fminf (100.0, (float) percentage ) ) );
// just policing a 'floor' and 'ceiling'...
swooshView.layer.mask = [self maskImageOfSize:self.swoosh.bounds.size filledTo:percentage];
}
Within my app, I use drawRect to draw some text within a UIImage. It writes multiple things in multiple places.. Later, I try to erase some of the text by using
CGContextSetBlendMode(context, kCGBlendModeClear);
CGPoint daPoint = CGPointMake(second.x + 20, second.y + 20);
NSDictionary *textAttributes = #{ NSFontAttributeName: [UIFont boldSystemFontOfSize:25.0],
NSForegroundColorAttributeName: [UIColor clearColor] };
[textString drawAtPoint:daPoint withAttributes:textAttributes];
This works almost perfectly, except there is a small thin stroke left over from the text. I use the same code to draw the text, as I do to erase, except when i'm drawing I use kCGBlendModeNormal. How would I get rid of it completely? Can I draw a box and fill it using kCGBlendModeClear? This is what it looks like currently before erasing:
After erasing:
I would get the bounding rect of the text and then call CGContextClearRect and then fill with the background color if you think that "erasing" the text is really necessary. If you simply "redraw" your rect, that might be another way to solve this problem.
Here's how to get that bounding box for clearing:
CGSize textSize = [textString sizeWithAttributes:textAttributes];
CGRect textFrame = CGRectMake(daPoint.x, daPoint.y, textSize.width, textSize.height);
Hope this helps!
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);
}
here is the problem I'm facing: I am making a UIScrollView which will have a pattern image to fill the background. That is to say, I need a background to scroll with the UIScrollView. A good example for this is the Game Center app, on the iPad. The background will scroll smoothly with scrollview.
Currently I have two ways to realize this effect, but neither of them offered good performance.
First I tried this
self.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:kRLCastViewBGUnit]];
but unfortunately, the scrolling performance was very bad and occupied too much memory.
Then I tried to use CGContextDrawTiledImage in the drawRect like this:
- (void)drawRect:(CGRect)rect
{
CGContextRef currentContext = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(currentContext, 0, rect.size.height);
CGContextScaleCTM(currentContext, 1.0, -1.0);
CGContextClipToRect(currentContext, rect);
CGRect centerTileRect = CenterTileRect;
CGContextDrawTiledImage(currentContext, centerTileRect, [ResourceProvider backgroundTileImageRef]);
}
It's still not satisfactory on the new iPad. I must have done something wrong or misused some methods, because the Game Center performs just great when it scrolls. Anyone can offer me a solution to solve the performance issue for the UIScrollView background? Thanks a lot!!
You should use an UITableView instead. In this you can set cell.backgroundView easily.
UIImageView *backgroundView = [[UIImageView alloc] initWithFrame:CGRectMake:(0.0,0.0,320.0, height)];
backgroundView.image = [UIImage imageNamed:#"Shelf.jpeg"];
cell.backgroundView = backgroundView;
And If you really want to use only UIScrollView then take only one cell background image and image width should be same of scrollView's width because colorWithPatternImage: method work like tiled property.
Take Only this image into your project and use it as backgroundColor of UIScrollView.
[scrollView setContentSize:CGSizeMake(320.0, 1000.0)];
[scrollView setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:#"cellImage.png"]]];
How can I set label's border which is dynamically generated (Not from Interface Builder)?
you can do it by
Label.layer.borderColor = [UIColor whiteColor].CGColor;
Label.layer.borderWidth = 4.0;
before this you need to import a framework QuartzCore/QuartzCore.h
Swift version
Set label border
label.layer.borderWidth = 2.0
Set border color
label.layer.borderColor = UIColor.blueColor().CGColor
Use rounded corners
label.layer.cornerRadius = 8
Make background color stay within rounded corners
label.layer.masksToBounds = true
You can also try to subclass your label and override the drawRect: method to draw or a border or whatever you like:
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
CGContextRef context = UIGraphicsGetCurrentContext();
[[UIColor blackColor] setStroke];
CGContextStrokeRect(context, self.bounds);
}
I'm not sure you can by default with UILabel. You might want to consider using a read-only (field.editing = NO) UITextField and setting it's borderStyle (which can be done programmatically using a UITextBorderStyle). That may be a little 'heavy' though. Another option may be to sub-class UILabel to draw your border.
Alternatively, and depending on your needs this may be better, use the backing CALayer and draw a border using it's borderColor and borderWidth properties.