I have three points, A,B and C, the code to link the three points as following
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext();
NSArray *points = #[ [NSValue valueWithCGPoint:CGPointMake(10.0f, 15.0f)],
[NSValue valueWithCGPoint:CGPointMake(100.0f, 170.0f)],
[NSValue valueWithCGPoint:CGPointMake(190.0f, 100.0f)],
];
CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
CGContextSetLineWidth(context, 2.0f);
CGContextSetLineJoin(context, kCGLineJoinRound);
CGContextSetLineCap(context, kCGLineCapRound);
for(int i = 0;i<points.count; ++i){
NSValue *pointValue = [points objectAtIndex:i];
CGPoint point = [pointValue CGPointValue];
if ( i == 0) {
CGContextMoveToPoint(context, point.x, point.y);
} else {
CGContextAddLineToPoint(context, point.x, point.y);
}
}
CGContextStrokePath(context);
}
However, the junction of two lines is an angle, I need to join point B with a round corder. like following image:
how to do it?
What you have is 2 straight lines, what you're asking for is (possibly 2 straight lines, joined by) an arc / bezier curve.
Look at using CGPathAddArcToPoint or CGPathAddCurveToPoint or CGPathAddQuadCurveToPoint.
Related
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.
Background:
I'm making an app that is grid-based using ARC. Basically there is a 4x4-8x8 grid in the center of the screen (that takes up most of the screen). This grid is constructed using a single UIView that is tinted some color and lines drawn with drawRect: (I'll be posting all of the relevant code below for reference).
Each of the cells is contained inside an NSMutableArray for each row that is contained inside another NSMutableArray of the rows:
Array (Rows)
Array (Cols)
Cell Contents
In each of these cells, I either have an actor object or a placeholder object. The placeholder object is essentially just a blank NSObject while the actor object has 8 primitive properties and 1 object property.
For instance, one of the actors is a source, which essentially recursively draws a plain UIView from the source across the grid until it hits another actor or a wall of the grid.
The blue and red lines show different UIViews as they are currently running. With a grid this small, memory doesn't seem to be an issue often; however, when the full game runs with an 8x8 grid, there can feasibly be 50+ drawn UIViews on the screen in addition to the UIImageViews that function as the sources, movables, etc. as well as the other UILabels and buttons that are not included in the grid. There can easily be over 100 UIViews on the screen at once, which, even on the latest devices with the best hardware, causes some pretty bad lag.
I have a feeling that this has to do with the fact that I am rendering 100+ views to the screen at once.
Question:
Can I incorporate all of these dynamically drawn lines into one view, or is there a better solution entirely?
drawRect:
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorRef color = [[self backgroundColor] CGColor];
int numComponents = CGColorGetNumberOfComponents(color);
CGFloat red = 0, green = 0, blue = 0;
if (numComponents == 4)
{
const CGFloat *components = CGColorGetComponents(color);
red = components[0];
green = components[1];
blue = components[2];
}
CGContextSetRGBFillColor(context, red, green, blue, 0.5);
float top;
float cell = [self cellWidth];
float grid = [self gridWidth];
//Draw
for(int i = 0; i < [self size]+1; i++)
{
top = i*(cell+lineWidth);
CGContextFillRect(context, CGRectMake(0, top, grid, lineWidth));
CGContextFillRect(context, CGRectMake(top, 0, lineWidth, grid));
}
}
addSources:
- (void)addSources:(NSArray*)sources
{
for(int i = 0; i < [sources count]; i++)
{
NSArray* src = [sources objectAtIndex:i];
int row = [[src objectAtIndex:1] intValue];
int column = [[src objectAtIndex:0] intValue];
int direction = [[src objectAtIndex:2] intValue];
int color = [UIColor colorKeyForString:[src objectAtIndex:3]];
float width = [self cellWidth]*scaleActors;
float x = lineWidth + (([self cellWidth]+lineWidth) * (column-1)) + (([self cellWidth]-width)/2.0);
float y = lineWidth + (([self cellWidth]+lineWidth) * (row-1)) + (([self cellWidth]-width)/2.0);
ActorView* actor = [[ActorView alloc] initWithFrame:CGRectMake(x, y, width, width)];
[actor setType:4];
[actor setDirection:direction];
[actor setColorKey:color];
[actor setIsGlowing:YES];
[actor setPicture];
if([self isCreatingLevel])
[actor setCanRotate:YES];
[self addSubview:actor];
[[[self rows] objectAtIndex:(row-1)] replaceObjectAtIndex:(column-1) withObject:actor];
}
}
Edit: Time Profiler Results
By this point, I have roughly 48 drawn views on the screen, (about 70 views total).
I'd suggest WWDC 2012 video iOS App Performance: Responsiveness as a good primer in using Instruments to track down these sorts of issues. Lots of good techniques and tips in that video.
But I agree that this number of views doesn't seem outlandish (though I might be tempted to render this all in CoreGraphics). I'm not using your same model, but here is a pure Core Graphics rendering of that graphic with a single UIView subclass:
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
// configure the gridlines
CGContextSetStrokeColorWithColor(context, [[UIColor blackColor] CGColor]);
CGContextSetLineWidth(context, 8.0);
CGContextSetLineCap(context, kCGLineCapSquare);
// add the horizontal gridlines
for (NSInteger row = 0; row <= self.rows; row++)
{
CGPoint from = [self coordinateForX:0 Y:row];
CGPoint to = [self coordinateForX:_cols Y:row];
CGContextMoveToPoint(context, from.x, from.y);
CGContextAddLineToPoint(context, to.x, to.y);
}
// add the vertical gridlines
for (NSInteger col = 0; col <= self.cols; col++)
{
CGPoint from = [self coordinateForX:col Y:0 ];
CGPoint to = [self coordinateForX:col Y:_rows];
CGContextMoveToPoint(context, from.x, from.y);
CGContextAddLineToPoint(context, to.x, to.y);
}
// stroke the gridlines
CGContextStrokePath(context);
// now configure the red/blue line segments
CGContextSetLineWidth(context, self.bounds.size.width / _cols / 2.0);
CGContextSetLineCap(context, kCGLineCapRound);
// iterate through our array of points
CGPoint lastPoint = [self.points[0] CGPointValue];
for (NSInteger i = 1; i < [self.points count]; i++)
{
// set the color
if (i % 2)
CGContextSetStrokeColorWithColor(context, [[UIColor redColor] CGColor]);
else
CGContextSetStrokeColorWithColor(context, [[UIColor blueColor] CGColor]);
CGPoint nextPoint = [self.points[i] CGPointValue];
// create path
CGPoint from = [self coordinateForCenterX:lastPoint.x Y:lastPoint.y];
CGPoint to = [self coordinateForCenterX:nextPoint.x Y:nextPoint.y];
CGContextMoveToPoint(context, from.x, from.y);
CGContextAddLineToPoint(context, to.x, to.y);
// stroke it
CGContextStrokePath(context);
// save the last point
lastPoint = nextPoint;
}
}
Now, maybe you're doing something else that requires more sophisticated treatment, in which case that WWDC video (or, perhaps iOS App Performance: Graphics and Animations) should point you in the right direction.
I am using Quartz 2D in a UIView object to draw several curves, like this example:
This is the code I have right now (I have omitted the calculation of control points and other stuff):
for (int i = 1; i < points.count; ++i) {
CGContextMoveToPoint(context, previousXValue, previousYValue);
CGContextAddCurveToPoint(context,
firstControlPointXValue, firstControlPointYValue,
secondControlPointXValue, secondControlPointYValue,
xValue, yValue
);
// CGContextFillPath(context);
CGContextStrokePath(context);
}
Now I would like to fill the area below the curve, but if I use CGContextFillPath the result is the following:
which makes sense, because according to Quartz 2D documentation:
When you fill the current path, Quartz acts as if each subpath contained in the path were closed. It then uses these closed subpaths
and calculates the pixels to fill.
Then I tried to move the path to the lower right corner and close the path, but the fill method doesn't have any effect:
CGContextMoveToPoint(context, rect.size.width, rect.size.height);
CGContextClosePath(context);
CGContextFillPath(context);
How could I fill the whole area below the curve and not just the subarea closed in every subpath?
EDIT:
I have found a temporary solution: drawing a shape using the curve and two vertical lines on each subpath:
for (int i = 1; i < points.count; ++i) {
// Draw the curve
CGContextMoveToPoint(context, previousXValue, previousYValue);
CGContextAddCurveToPoint(context,
firstControlPointXValue, firstControlPointYValue,
secondControlPointXValue, secondControlPointYValue,
xValue, yValue
);
CGContextStrokePath(context);
// Draw a shape using curve's initial and final points
CGContextMoveToPoint(context, previousXValue, rect.size.height);
CGContextAddLineToPoint(context, previousXValue, previousYValue);
CGContextAddCurveToPoint(context,
firstControlPointXValue, firstControlPointYValue,
secondControlPointXValue, secondControlPointYValue,
xValue, yValue
);
CGContextAddLineToPoint(context, xValue, rect.size.height);
CGContextFillPath(context);
}
I don't know if this is overkill, so improvements are also welcomed. Besides, I'm getting this result:
Note that vertical lines appear as a result of drawing the subareas next to each other. How can that be avoided?
The idea is right, but you should not fill the individual curves, but rather, create a single path and then fill that. So, start with CGContextMoveToPoint to the lower left corner, CGContextAddLineToPoint to your first point, do the CGContextAddCurveToPoint for all of the curves, and at the end, do a CGContextAddLineToPoint to the lower right corner (and you might as well do a CGContextClosePath for good measure).
This is a simplified example, where I just have an array of points, but it illustrates the idea:
- (void)drawRect:(CGRect)rect
{
if (!self.points)
[self configurePoints];
DataPoint *point;
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorRef color = [[UIColor redColor] CGColor];
CGContextSetStrokeColorWithColor(context, color);
CGContextSetFillColorWithColor(context, color);
point = self.points[0];
CGContextMoveToPoint(context, point.x, self.bounds.size.height);
CGContextAddLineToPoint(context, point.x, point.y);
for (point in self.points)
{
// you'd do your CGContextAddCurveToPoint here; I'm just adding lines
CGContextAddLineToPoint(context, point.x, point.y);
}
point = [self.points lastObject];
CGContextAddLineToPoint(context, point.x, self.bounds.size.height);
CGContextClosePath(context);
CGContextDrawPath(context, kCGPathFillStroke);
}
i'm drawing a graph and i want the the ascending lines to be in green and the descending lines in red. i tried the following:
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 2);
CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
CGPoint previousPoint = CGPointMake(0.0, 0.0);
//graph the points
for (int i = 0; i < self.numberOfS; i++) {
CGPoint currentPoint = CGPointMake(150+(40*[[[self.grades objectAtIndex:i] s] doubleValue]), 59+(40*(i+1)));
if (previousPoint.x != 0.0f) {
if (previousPoint.x > currentPoint.x) {
CGContextMoveToPoint(context, previousPoint.x, previousPoint.y);
CGContextSetStrokeColorWithColor(context, [UIColor greenColor].CGColor);
CGContextAddLineToPoint(context, 150+(40*[[[self.grades objectAtIndex:i] semesterGPA] doubleValue]), 59+(40*(i+1)));
} else{
CGContextMoveToPoint(context, previousPoint.x, previousPoint.y);
CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
CGContextAddLineToPoint(context, 150+(40*[[[self.grades objectAtIndex:i] semesterGPA] doubleValue]), 59+(40*(i+1)));
}
}
previousPoint.x = currentPoint.x;
previousPoint.y = currentPoint.y;
}
but it's not working, everything is in red. how can i fix this ?
Ok solved the problem, i just entered this line of code:
CGContextStrokePath(context);
I'm working on the Stanford CS193p course and am trying to draw a graph. Drawing the axes works, but I can't draw the graph itself. I'm getting the message
CGContextAddLineToPoint: no current point.
when I try to draw. Here's the code.
- (void)drawRect:(CGRect)rect
{
NSLog(#"Drawing Graph View");
CGPoint origin = CGPointMake(20, 350);
CGRect rect2 = CGRectMake(origin.x, origin.y, 250, -250);
[AxesDrawer drawAxesInRect:rect2 originAtPoint:origin scale:[self scale]];
CGContextRef context = UIGraphicsGetCurrentContext();
UIGraphicsPushContext(context);
CGContextSetLineWidth(context, 2);
[[UIColor redColor] setStroke];
CGContextMoveToPoint(context, origin.x, origin.y);
for (CGFloat i=0; i<250; i++) {
CGFloat yChange = [self.dataSource deltaY:self];
CGContextAddLineToPoint(context, origin.x+i, origin.y-yChange);
CGContextStrokePath(context);
}
UIGraphicsPopContext();
}
You have to place CGContextStrokePath(context); outside the for loop. Otherwise it will create a fresh path on every run through the loop and that fails.
Do you not have a problem with:
CGRectMake(origin.x, origin.y, 250, -250)
You specify a negative height!