For an iPhone application I want to draw a circle, that is only for an x percentage filled.
Something like this:
I have no problems calculating the radius, the degrees or the radians, that is no problem. Also drawing the circle is already done. But how do I get the iPhone SDK to draw the part that is filled.
I can draw a rectangle that size, but not part of a circle.
I just want to draw that on a a normal context.
Hope someone can give me any pointers here.
A lot of people have showed you how this can be done in Core Graphics but it can also be done with Core Animation which gives the big addition of easily being able to animate the percentage of the pie shape.
The following code will create both the ring and the partly filled layers (even though you said that you already can draw the ring) since its nice to have both the ring and the pie shape to be drawn using the same method.
If you animate the strokeStart or strokeEnd properties of the pieShape layer you will have the percentage animate. As with all Core Animation code you will need to add QuartzCore.framework to your project and include <QuartzCore/QuartzCore.h> in your code.
// Create a white ring that fills the entire frame and is 2 points wide.
// Its frame is inset 1 point to fit for the 2 point stroke width
CGFloat radius = MIN(self.frame.size.width,self.frame.size.height)/2;
CGFloat inset = 1;
CAShapeLayer *ring = [CAShapeLayer layer];
ring.path = [UIBezierPath bezierPathWithRoundedRect:CGRectInset(self.bounds, inset, inset)
cornerRadius:radius-inset].CGPath;
ring.fillColor = [UIColor clearColor].CGColor;
ring.strokeColor = [UIColor whiteColor].CGColor;
ring.lineWidth = 2;
// Create a white pie-chart-like shape inside the white ring (above).
// The outside of the shape should be inside the ring, therefore the
// frame needs to be inset radius/2 (for its outside to be on
// the outside of the ring) + 2 (to be 2 points in).
CAShapeLayer *pieShape = [CAShapeLayer layer];
inset = radius/2 + 2; // The inset is updated here
pieShape.path = [UIBezierPath bezierPathWithRoundedRect:CGRectInset(self.bounds, inset, inset)
cornerRadius:radius-inset].CGPath;
pieShape.fillColor = [UIColor clearColor].CGColor;
pieShape.strokeColor = [UIColor whiteColor].CGColor;
pieShape.lineWidth = (radius-inset)*2;
// Add sublayers
// NOTE: the following code is used in a UIView subclass (thus self is a view)
// If you instead chose to use this code in a view controller you should instead
// use self.view.layer to access the view of your view controller.
[self.layer addSublayer:ring];
[self.layer addSublayer:pieShape];
Use CGContext's arc functions:
CGContextAddArc(context,
centerX,
centerY,
radius,
startAngleRadians,
endAngleRadians,
clockwise ? 1 : 0);
See the documentation for CGContextAddArc().
Try this:
CGContextMoveToPoint(the center point)
CGContextAddLineToPoint(the starting point of the fill path on the circumference)
CGContextAddArcToPoint(the ending point of the fill path on the circumference)
CGContextAddLineToPoint(the center point)
CGContextFillPath
I implemented a pie progress view that looks similar to what you are doing. It's open source. Hopefully the source code will help.
SSPieProgressView.h source
SSPieProgressView.m source
CircleViewController.h
#import <UIKit/UIKit.h>
#interface CircleViewController : UIViewController
#end
CircleViewController.m
#import "CircleViewController.h"
#import "GraphView.h"
#interface CircleViewController ()
#end
#implementation CircleViewController
- (void)viewDidLoad {
[super viewDidLoad];
GraphView *graphView = [[GraphView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];
graphView.backgroundColor = [UIColor whiteColor];
graphView.layer.borderColor = [UIColor redColor].CGColor;
graphView.layer.borderWidth = 1.0f;
[self.view addSubview:graphView];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
GraphView.h
#import <UIKit/UIKit.h>
#interface GraphView : UIView
#end
GraphView.m
#import "GraphView.h"
#implementation GraphView
- (void)drawRect:(CGRect)rect {
CGPoint circleCenter = CGPointMake(self.bounds.size.width / 2, self.bounds.size.height / 2);
[self drawCircleWithCircleCenter:(CGPoint) circleCenter radius:80 firstColor:[UIColor blueColor].CGColor secondeColor:[UIColor redColor].CGColor lineWidth:2 startDegree:0 currentDegree:90];
//[self drawCircleWithCircleCenter2:(CGPoint) circleCenter radius:80 firstColor:[UIColor blueColor].CGColor secondeColor:[UIColor redColor].CGColor lineWidth:2 startDegree:0 currentDegree:90];
}
- (void)drawCircleWithCircleCenter:(CGPoint) circleCenter
radius:(CGFloat)radius
firstColor:(CGColorRef)firstColor
secondeColor:(CGColorRef)secondeColor
lineWidth:(CGFloat)lineWidth
startDegree:(float)startDegree
currentDegree:(float)endDegree {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, lineWidth);
CGContextMoveToPoint(context, circleCenter.x, circleCenter.y);
CGContextAddArc(context, circleCenter.x , circleCenter.y, radius, [self radians:startDegree], [self radians:endDegree], 0);
CGContextSetFillColorWithColor(context, firstColor);
CGContextFillPath(context);
CGContextMoveToPoint(context, circleCenter.x, circleCenter.y);
CGContextAddArc(context, circleCenter.x, circleCenter.y, radius, [self radians:endDegree], [self radians:startDegree], 0);
CGContextSetFillColorWithColor(context, secondeColor);
CGContextFillPath(context);
}
- (void)drawCircleWithCircleCenter2:(CGPoint) circleCenter
radius:(CGFloat)radius
firstColor:(CGColorRef)firstColor
secondeColor:(CGColorRef)secondeColor
lineWidth:(CGFloat)lineWidth
startDegree:(float)startDegree
currentDegree:(float)endDegree {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, lineWidth);
CGContextMoveToPoint(context, circleCenter.x, circleCenter.y);
CGContextAddArc(context, circleCenter.x , circleCenter.y, radius, [self radians:startDegree], [self radians:endDegree], 0);
CGContextSetFillColorWithColor(context, firstColor);
CGContextFillPath(context);
CGContextMoveToPoint(context, circleCenter.x, circleCenter.y);
CGContextAddArc(context, circleCenter.x, circleCenter.y, radius, [self radians:endDegree], [self radians:startDegree], 0);
CGContextSetStrokeColorWithColor(context, secondeColor);
CGContextStrokePath(context);
}
-(float) radians:(double) degrees {
return degrees * M_PI / 180;
}
#end
note: you can use one of the 2 methods:
"drawCircleWithCircleCenter" or "drawCircleWithCircleCenter2"
this code if you want to split cell on 2 parts only
if you want to split cell on more than 2 parts you can check this : "Drawing a circle ,filled different parts with different color" and check the answer start with this Phrase "we have 6 class"
Well, since nobody used NSBezierPath so far, I figured I could provide the solution I recently used for the same problem:
-(void)drawRect:(NSRect)dirtyRect
{
double start = -10.0; //degrees
double end = 190.0; //degrees
NSPoint center = NSMakePoint(350, 200);
double radius = 50;
NSBezierPath *sector = [NSBezierPath bezierPath];
[sector moveToPoint:center];
[sector appendBezierPathWithArcWithCenter:center radius:radius startAngle:start endAngle:end];
[sector lineToPoint:center];
[sector fill];
}
Below is a full method I am using that does this with Core Graphics, adapting and expanding on mharper's comment above.
This code is for OSX Cocoa, but could easily be changed to iOS, by modifying how you get the context.
- (void)drawPieShapedCircleWithRadius:(CGFloat)radius
strokeColor:(CGColorRef)strokeColor
fillColor:(CGColorRef)fillColor
lineWidth:(CGFloat)lineWidth
currentDegrees:(float)currentDegrees
startDegrees:(float)startDegrees {
// get the context
CGContextRef context = [[NSGraphicsContext currentContext] graphicsPort];
// Set the color of the circle stroke and fill
CGContextSetStrokeColorWithColor(context, strokeColor);
CGContextSetFillColorWithColor(context, fillColor);
// Set the line width of the circle
CGContextSetLineWidth(context, 1);
// Calculate the middle of the circle
CGPoint circleCenter = CGPointMake(self.frame.size.width / 2, self.frame.size.height / 2);
// Move the bezier to the center of the circle
CGContextMoveToPoint(context, circleCenter.x, circleCenter.y); // move to the center point
// Draw the arc from the start point (hardcoded as the bottom of the circle) to the center
CGContextAddLineToPoint(context, circleCenter.x, circleCenter.y + radius);
// Draw the arc around the circle from the start degrees point to the current degrees point
CGContextAddArc(context, circleCenter.x , circleCenter.y, radius, [self radians:startDegrees], [self radians:startDegrees + currentDegrees], 0);
// Draw the line back into the center of the circle
CGContextAddLineToPoint(context, circleCenter.x, circleCenter.y);
// Fill the circle
CGContextFillPath(context);
// Draw the line around the circle
CGContextStrokePath(context);
}
Try this code in a UIView, Example "MyChartClass"...
- (void)drawRect:(CGRect)rect {
int c=(int)[itemArray count];
CGFloat angleArray[c];
CGFloat offset;
int sum=0;
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetAllowsAntialiasing(context, false);
CGContextSetShouldAntialias(context, false);
for(int i=0;i<[itemArray count];i++) {
sum+=[[itemArray objectAtIndex:i] intValue];
}
for(int i=0;i<[itemArray count];i++) {
angleArray[i]=(float)(([[itemArray objectAtIndex:i] intValue])/(float)sum)*(2*3.14);
CGContextMoveToPoint(context, radius, radius);
if(i==0)
CGContextAddArc(context, radius, radius, radius, 0,angleArray[i], 0);
else
CGContextAddArc(context, radius, radius, radius,offset,offset+angleArray[i], 0);
offset+=angleArray[i];
CGContextSetFillColorWithColor(context, ((UIColor *)[myColorArray objectAtIndex:i]).CGColor);
CGContextClosePath(context);
CGContextFillPath(context);
}
}
Implementation in your UIViewController
MyChartClass *myChartClass=[[MyChartClass alloc]initWithFrame:CGRectMake(0, 0, 200, 200)];
myChartClass.backgroundColor = [UIColor clearColor];
myChartClass.itemArray=[[NSArray alloc]initWithObjects:#"75",#"25", nil];
myChartClass.myColorArray=[[NSArray alloc]initWithObjects:[UIColor blackColor],[UIColor whiteColor], nil];
myChartClass.radius=100;
[self.view addSubview:myChartClass];
Regards.
I came up with a scenario like drawing a line graph using DrawRect method. Using the same code i should plot three more types of line graphs. How should i clear already plotted graph and draw another...Posting one of the clasess drawRect method. Please look at it and suggest me a solution for this
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClearRect(context, self.bounds);
CGContextSetAllowsAntialiasing(context, true);
CGRect currentBounds = self.bounds;
CGFloat dotsWidth = self.numberOfPages*kDotDiameter + MAX(0, self.numberOfPages-1)*kDotSpacer;
CGFloat x = CGRectGetMidX(currentBounds)-dotsWidth/2;
CGFloat y = CGRectGetMidY(currentBounds)-kDotDiameter/2;
for (int i=0; i<_numberOfPages; i++)
{
CGRect circleRect = CGRectMake(x, y, kDotDiameter, kDotDiameter);
if (i == _currentPage)
{
CGContextSetFillColorWithColor(context, [UIColor orangeColor].CGColor);
}
else
{
CGContextSetFillColorWithColor(context, [UIColor whiteColor].CGColor);
}
CGContextFillEllipseInRect(context, circleRect);
x += kDotDiameter + kDotSpacer;
}
}
You can try the following, rect should be containing the line graph bounds.
CGContextClearRect(UIGraphicsGetCurrentContext(), rect);
This question already has answers here:
What's the best approach to draw lines between views?
(2 answers)
Closed 9 years ago.
I have a very simple (well hopefully very simple) question. In Objective-C, how do you draw a line between two points and add it to a UIView? I have tried using a UIImageView and manipulating its Transform property, but that ends up turning the line into a square or a rectangle when using the following code:
[[self tline] setFrame:CGRectMake(start.x, start.y, width, 5)];
[[self tline] setTransform:CGAffineTransformMakeRotation(angle)];
I have two CGPoints, start and end, and I would like to draw a dynamic 5px line between the two points and add it to my subview.
BK:
The point start is the point where the user begins touching the screen, and the point end is the point where the user's finger is currently. Obviously this will move a lot during gameplay. I need to be able to move this line to connect these two points.
I am using the touchesBegan:, Moved:, and Ended: methods to create, move, and destroy the line.
CoreGraphics
I have the following code; how do I add this line to self.view?
CGContextRef c = UIGraphicsGetCurrentContext();
CGFloat color[4] = {1.0f, 1.0f, 1.0f, 0.6f};
CGContextSetStrokeColor(c, color);
CGContextBeginPath(c);
CGContextMoveToPoint(c, start.x, start.y);
CGContextAddLineToPoint(c, end.x, end.y);
CGContextSetLineWidth(c, 5);
CGContextSetLineCap(c, kCGLineCapRound);
CGContextStrokePath(c);
Custom UIView:
#import <UIKit/UIKit.h>
#interface DrawingView : UIView
#property (nonatomic) CGPoint start;
#property (nonatomic) CGPoint end;
- (void)drawRect:(CGRect)rect;
#end
#import "DrawingView.h"
#implementation DrawingView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGContextSetLineCap(context, kCGLineCapSquare);
CGContextSetStrokeColorWithColor(context, [UIColor whiteColor].CGColor); //change color here
CGFloat lineWidth = 5.0; //change line width here
CGContextSetLineWidth(context, lineWidth);
CGPoint startPoint = [self start];
CGPoint endPoint = [self end];
CGContextMoveToPoint(context, startPoint.x + lineWidth/2, startPoint.y + lineWidth/2);
CGContextAddLineToPoint(context, endPoint.x + lineWidth/2, endPoint.y + lineWidth/2);
CGContextStrokePath(context);
CGContextRestoreGState(context);
NSLog(#"%f",_end.x);
}
- (void)setEnd:(CGPoint)end
{
_end = end;
[self setNeedsDisplay];
}
#end
drawRect: is only called when I initialize the view...
Draw method in UIViewController:
- (void)drawTLine:(CGPoint)start withEndPoint:(CGPoint)end
{
[[self dview] setStart:start];
[[self dview] setEnd:end];
[[self dview] drawRect:[self dview].frame];
}
This is how I add the drawing view:
DrawingView* dview = [[DrawingView alloc] initWithFrame:self.view.frame];
[dview setBackgroundColor:[UIColor clearColor]];
[self.view addSubview:dview];
Subclass UIView and perform custom drawing using the drawRect: method
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGContextSetLineCap(context, kCGLineCapSquare);
CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor); //change color here
CGFloat lineWidth = 1.0; //change line width here
CGContextSetLineWidth(context, lineWidth);
CGPoint startPoint = rect.origin; //change start point here
CGPoint endPoint = {.x = CGRectGetMaxX(rect), .y = startPoint.y} //change end point here
CGContextMoveToPoint(context, startPoint.x + lineWidth/2, startPoint.y + lineWidth/2);
CGContextAddLineToPoint(context, endPoint.x + lineWidth/2, endPoint.y + lineWidth/2);
CGContextStrokePath(context);
CGContextRestoreGState(context);
}
This will draw a black 1px line at the top of your UIView.
If you need to update the line you can just use some properties like
#property (nonatomic) CGPoint startPoint;
and provide a custom implementation for the setter like
- (void)setStartPoint:(CGPoint)point {
_point = point;
[self setNeedsDisplay]; // this will cause drawRect: to be called again
}
Do that for every property that you wish to control and make your drawRect: use such properties for drawing.
you can create and UIBezierPath like this
UIBezierPath path = [[UIBezierPath alloc] init]
[path moveToPoint: CGPoint(x,y)] // X and Y, start point
[path addLineToPoint:CGPoint(x2,y2) // X2 and Y2, end point
if you want to create a shape you can put more points with addLineToPoint: method and finish use
closePath method
I hope help you
I am trying to implement a custom UIView which is basically a pie menu (something like a cake divided into slices).
For that I am trying to draw a circle and a series of lines from the center, like the rays in a chart's wheel.
I have successfully drawn the circle and and I would now like to draw the lines dividing the circle in slices.
This is what I have so far:
-(void)drawRect:(CGRect)rect{
[[UIColor blackColor] setStroke];
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGFloat minDim = (rect.size.width < rect.size.height) ? rect.size.width : rect.size.height;
CGRect circleRect = CGRectMake(0, rect.size.height/2-minDim/2, minDim, minDim);
CGContextAddEllipseInRect(ctx, circleRect);
CGContextSetFillColor(ctx, CGColorGetComponents([[UIColor yellowColor] CGColor]));
CGContextFillPath(ctx);
CGPoint start = CGPointMake(0, rect.size.height/2);
CGPoint end = CGPointMake(rect.size.width, rect.size.height/2);
for (int i = 0; i < MaxSlices(6); i++){
CGFloat degrees = 1.0*i*(180/MaxSlices(6));
CGAffineTransform rot = CGAffineTransformMakeRotation(degreesToRadians(degrees));
UIBezierPath *path = [self pathFrom:start to:end];
[path applyTransform:rot];
}
}
- (UIBezierPath *) pathFrom:(CGPoint) start to:(CGPoint) end{
UIBezierPath* aPath = [UIBezierPath bezierPath];
aPath.lineWidth = 5;
[aPath moveToPoint:start];
[aPath addLineToPoint:end];
[aPath closePath];
[aPath stroke];
return aPath;
}
The problem is that applyTransform on the path doesn't seem to do anything. The first path gest drawn correctly the and the following ones are unaffected by the rotation. Basically what I see is just one path. Check the screen shot here http://img837.imageshack.us/img837/9757/iossimulatorscreenshotf.png
Thank you for your help!
You're drawing the path (with stroke) before you transform it. A path is just a mathematical representation. It isn't the line "on the screen." You can't move what you've already drawn by modifying the data about it.
Just move the [aPath stroke] out of pathFrom:to: and put it after the applyTransform:.
I have a UIView subclass on which the user can add a random CGPath. The CGPath is added by processing UIPanGestures.
I would like to resize the UIView to the minimal rect possible that contains the CGPath. In my UIView subclass, I have overridden sizeThatFits to return the minimal size as such:
- (CGSize) sizeThatFits:(CGSize)size {
CGRect box = CGPathGetBoundingBox(sigPath);
return box.size;
}
This works as expected and the UIView is resized to the value returned, but the CGPath is also "resized" proportionally resulting in a different path that what the user had originally drawn. As an example, this is the view with a path as drawn by the user:
And this is the view with the path after resizing:
How can I resize my UIView and not "resize" the path?
Use the CGPathGetBoundingBox. From Apple documentation:
Returns the bounding box containing all points in a graphics path. The
bounding box is the smallest rectangle completely enclosing all points
in the path, including control points for Bézier and quadratic curves.
Here a small proof-of-concept drawRect methods. Hope it helps you!
- (void)drawRect:(CGRect)rect {
//Get the CGContext from this view
CGContextRef context = UIGraphicsGetCurrentContext();
//Clear context rect
CGContextClearRect(context, rect);
//Set the stroke (pen) color
CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);
//Set the width of the pen mark
CGContextSetLineWidth(context, 1.0);
CGPoint startPoint = CGPointMake(50, 50);
CGPoint arrowPoint = CGPointMake(60, 110);
//Start at this point
CGContextMoveToPoint(context, startPoint.x, startPoint.y);
CGContextAddLineToPoint(context, startPoint.x+100, startPoint.y);
CGContextAddLineToPoint(context, startPoint.x+100, startPoint.y+90);
CGContextAddLineToPoint(context, startPoint.x+50, startPoint.y+90);
CGContextAddLineToPoint(context, arrowPoint.x, arrowPoint.y);
CGContextAddLineToPoint(context, startPoint.x+40, startPoint.y+90);
CGContextAddLineToPoint(context, startPoint.x, startPoint.y+90);
CGContextAddLineToPoint(context, startPoint.x, startPoint.y);
//Draw it
//CGContextStrokePath(context);
CGPathRef aPathRef = CGContextCopyPath(context);
// Close the path
CGContextClosePath(context);
CGRect boundingBox = CGPathGetBoundingBox(aPathRef);
NSLog(#"your minimal enclosing rect: %.2f %.2f %.2f %.2f", boundingBox.origin.x, boundingBox.origin.y, boundingBox.size.width, boundingBox.size.height);
}