I want to make UIView which is originally rectangular to Hexagon shape to be used in my application.
Please help me something on this.
Thanks in advance.
Subclass UView and override drawRect to draw a hexagon like so:
- (void)drawRect:(CGRect)rect
{
float polySize = 60; // change this
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGAffineTransform t0 = CGContextGetCTM(context);
t0 = CGAffineTransformInvert(t0);
CGContextConcatCTM(context, t0);
//Begin drawing setup
CGContextBeginPath(context);
CGContextSetRGBStrokeColor(context, 0, 0, 0, 1);
CGContextSetLineWidth(context, 2.0);
CGPoint center;
//Start drawing polygon
center = CGPointMake(160, 90.0);
CGContextMoveToPoint(context, center.x, center.y + polySize);
for(int i = 1; i < 6; ++i)
{
CGFloat x = polySize * sinf(i * 2.0 * M_PI / 6);
CGFloat y = polySize * cosf(i * 2.0 * M_PI / 6);
CGContextAddLineToPoint(context, center.x + x, center.y + y);
}
//Finish Drawing
CGContextClosePath(context);
CGContextDrawPath(context, kCGPathStroke);
CGContextRestoreGState(context);
}
You can create a subclass of UIView and in it's -(void)drawRect: method draw a hexagon. Or Use UIImageView with image of hexagon
Related
I'm attempting to draw a translucent black rectangle with a triangle cut out of the center.
I have this working perfectly with the code below. However, I'd like to round the corners of the triangle.
I've tried a couple of different techniques for adding rounded corners such as setting CGContextSetLineCap for a stroke and by creating my path with quartz and using CGContextAddArcToPoint, but I've failed to get anything to work.
As I mentioned, the code below works for a triangle cutout. How can I round the corners of the triangle?
CGContextRef context = UIGraphicsGetCurrentContext();
CGPoint position = CGPointMake(rect.size.width/2, rect.size.height * .7);
CGSize size = CGSizeMake(rect.size.width*.8, rect.size.height*.5);
CGFloat firstPointX = (position.x - (size.width / 2));
CGFloat firstPointY = (position.y - (size.height));
CGPoint firstPoint = CGPointMake(firstPointX, firstPointY);
CGFloat secondPointX = position.x + (size.width / 2);
CGFloat secondPointY = position.y - (size.height);
CGPoint secondPoint = CGPointMake(secondPointX, secondPointY);
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:position];
[path addLineToPoint:firstPoint];
[path moveToPoint:firstPoint];
[path addLineToPoint:secondPoint];
[path addLineToPoint:position];
[path closePath];
CGContextAddRect(context, rect);
CGContextAddPath(context, path.CGPath);
CGContextEOClip(context);
UIColor *translucentColor = [UIColor colorWithWhite:0 alpha:0.5];
CGContextSetFillColorWithColor(context, translucentColor.CGColor);
CGContextFillRect(context, rect);
UIGraphicsEndImageContext();
EDIT: Here's an example of what I'm trying to accomplish.
I think you want to use CGContextAddArc. It draws part of a circle with a line leading up to it if necessary. Here's the code to draw a rounded box that fills a UIView. For a triangle you'd have 3 lines instead of 4. Two on the top and one in the middle on the bottom. This is from a roundBoxView class I have:
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect boxRect = self.bounds;
float bRadius = self.cornerRadius;
float shrink = self.strokeThickness/2;
CGContextBeginPath(context);
// instead of this gray you could later add options for other colors
CGContextSetGrayFillColor(context, 0.0f, self.backgroundOpacity);
CGContextMoveToPoint(context, CGRectGetMinX(boxRect)+shrink + bRadius, CGRectGetMinY(boxRect)+shrink);
CGContextAddArc(context, CGRectGetMaxX(boxRect)-shrink - bRadius, CGRectGetMinY(boxRect)+shrink + bRadius, bRadius, 3 * (float)M_PI / 2, 0, 0);
CGContextAddArc(context, CGRectGetMaxX(boxRect)-shrink - bRadius, CGRectGetMaxY(boxRect)-shrink - bRadius, bRadius, 0, (float)M_PI / 2, 0);
CGContextAddArc(context, CGRectGetMinX(boxRect)+shrink + bRadius, CGRectGetMaxY(boxRect)-shrink - bRadius, bRadius, (float)M_PI / 2, (float)M_PI, 0);
CGContextAddArc(context, CGRectGetMinX(boxRect)+shrink + bRadius, CGRectGetMinY(boxRect)+shrink + bRadius, bRadius, (float)M_PI, 3 * (float)M_PI / 2, 0);
CGContextClosePath(context);
CGContextFillPath(context);
Of course instead of the boxRect being the full bounds you could pass that to your method and draw it using whatever bounds you want. To make it a triangle you would only have the 3 lines instead of two and you might have to do some math to figure out the start and end angles. On a box those angles are always 90 degrees (here given is icky radians) but on a triangle you'll either have to calc the angles on the fly or have a preset aspect ratio on the triangle so you can use preset start and stop angles. In the example as pictured with 3 equal angles you'd do 120 degrees or M_PI / 1.5 sized steps.
I have made a subclass of UIView and I am trying to draw part of a circle in my drawRect method.
I have tried using bezierPathWithArcCenter and filling it but that only result in a pie shape (image 3) and that's not what i'm after. I want to draw what you see in image 1 and 2.
Maybe I can clip a full circle somehow? The area around the circle needs to be transparent.
TompaLompas answer pointed me in the right direction (with the arc drawing part). However the complete solution and answer is like this:
#define DEGREES_TO_RADIANS(degrees) ((M_PI * degrees)/ 180)
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
CGContextRef ctx = UIGraphicsGetCurrentContext();
int radius = self.frame.size.width / 2;
CGPoint center = CGPointMake(self.frame.size.width / 2, self.frame.size.height / 2);
//Image 2
CGContextSetFillColorWithColor(ctx, [UIColor redColor].CGColor);
CGContextAddArc(ctx, center.x, center.y, radius, DEGREES_TO_RADIANS(225), DEGREES_TO_RADIANS(315), NO);
CGContextDrawPath(ctx, kCGPathFill);
}
try overriding drawRect with this:
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
CGContextRef context = UIGraphicsGetCurrentContext();
float radius = 50.0f;
float x_left = rect.origin.x;
float x_left_center = x_left + radius;
float y_top = rect.origin.y;
float y_top_center = y_top + radius;
/* Begin path */
CGFloat white[4] = {0.0f, 204.0f/255.0f, 1.0f, 0.8f};
CGContextSetFillColor(context, white);
CGContextSetLineWidth(context, 1.0);
CGContextBeginPath(context);
CGContextMoveToPoint(context, x_left, y_top_center);
CGContextAddArcToPoint(context, x_left, y_top, x_left_center, y_top, radius);
CGContextAddLineToPoint(context,x_left, y_top + radius);
CGContextFillPath(context);
}
It will draw a rotated image number 2
I write a msg background in tableviewcell, but when scrolling, the view become different. seems like the "context" store some state.
The code draw a round rect with a arrow.The arrow size should be fixed,but in fact it will change sometimes then scrolling.
- (void)drawRect:(CGRect)rect
{
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext();
CGFloat width = self.frame.size.width;
CGFloat height = self.frame.size.height;
CGFloat arrowHeight = 10;
CGFloat arrowWidth = 5;
CGFloat arrowOffset = 5;
CGFloat radius = 5;
CGFloat shadowHeight = 2;
CGFloat shadowOffset = 4;
CGColorRef shadowColor = [UIColor colorWithRed:0.2f
green:0.2f
blue:0.2f
alpha:0.5f].CGColor;
CGColorRef color;
color = [UIColor whiteColor].CGColor;
CGContextSaveGState(context);
CGContextMoveToPoint(context, width/2, 0);
CGContextAddArcToPoint(context, width - arrowWidth, 0, width - arrowWidth, height - shadowOffset, radius);
CGContextAddLineToPoint(context, width - arrowWidth, arrowOffset);
CGContextAddLineToPoint(context, width, arrowOffset + arrowHeight/2);
CGContextAddLineToPoint(context, width - arrowWidth, arrowOffset + arrowHeight);
CGContextAddArcToPoint(context, width - arrowWidth, height - shadowOffset, shadowOffset, height - shadowOffset, radius);
CGContextAddArcToPoint(context, shadowOffset, height - shadowOffset, shadowOffset, 0, radius);
CGContextAddArcToPoint(context, shadowOffset, 0, width, 0, radius);
CGContextSetShadowWithColor(context, CGSizeMake(0, shadowHeight), 3.0, shadowColor);
CGContextSetFillColorWithColor(context, color);
CGContextFillPath(context);
CGContextRestoreGState(context);
}
the effect like this:
I find the problem. the view should redraw when cell is reused,or the view will use the view in last cell to show.
so, just call [theView setNeedsDisplay] to let the view call drawRect again.
I want to draw a gradient inside a polygon using core graphics. I am able to draw a hexagon using the code below but i don't know how to fill this hexagon with a gradient color. Any help will be really appreciated.
- (void)drawRect:(CGRect)rect
{
// Drawing code.
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);
CGContextSetLineWidth(context, 2.0);
CGPoint center;
center = CGPointMake(210.0, 90.0);
CGContextMoveToPoint(context, center.x, center.y + 60.0);
for(int i = 1; i < 6; ++i)
{
CGFloat x = 60.0 * sinf(i * 2.0 * M_PI / 6.0);
CGFloat y = 60.0 * cosf(i * 2.0 * M_PI / 6.0);
CGContextAddLineToPoint(context, center.x + x, center.y + y);
}
CGContextClosePath(context);
CGContextDrawPath(context, kCGPathFillStroke);
}
Use following code for Gradient fill
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB();
CGFloat colors[] =
{
0.62890625, 0.859375, 10.9921875, 1.00,
0.65625, 0.8046875, 0.9453125, 1.00,
};
CGGradientRef gradient = CGGradientCreateWithColorComponents(rgb, colors, NULL, sizeof(colors)/(sizeof(colors[0])*4));
CGColorSpaceRelease(rgb);
// now we can actually create the shape and fill it
CGPoint start, end;
CGContextSetRGBFillColor(context, 0, 0, 0.6, 0.1);
CGContextFillEllipseInRect(context, CGRectMake(0.0, 0.0, 100.0, 100.0));
CGContextStrokeEllipseInRect(context, CGRectMake(0.0, 0.0, 100.0, 100.0));
// Gradient
CGRect myrect = CGRectMake(0.0, 0.0, rect.size.width, rect.size.height);
CGContextSaveGState(context);
CGContextClipToRect(context, myrect);
start = CGPointMake(myrect.origin.x, myrect.origin.y + myrect.size.height * 0.25);
end = CGPointMake(myrect.origin.x, myrect.origin.y + myrect.size.height * 1.0);
CGContextDrawLinearGradient(context, gradient, start, end, kCGGradientDrawsBeforeStartLocation);
CGContextRestoreGState(context);
I am trying to draw grid on a UIView on a UIScrollView.
The width of UIView is about 1000 pixels. However, I can draw lines only
about first 340 pixels of the UIView. Can anyone help me on this?
The drawGrid function is
- (void)drawRect:(CGRect)rect
{
NSInteger width = 25 * 5 * 10;
NSInteger height = (10 * 2 + 10) * 12;
NSInteger i;
//Get the CGContext from this view
CGContextRef context = UIGraphicsGetCurrentContext();
// Draw rectangle with a blue stroke color and white fill color
CGContextSetRGBStrokeColor(context, 0.0, 0.0, 1.0, 1.0);
CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);
CGContextSetLineWidth(context, 2.0);
CGContextAddRect(context, CGRectMake(0.0, 0.0, width, height));
CGContextFillPath(context);
// Draw grid with red color
CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
// Set the width of the pen mark
CGContextSetLineWidth(context, 0.2);
for (i = 0; i < height; i += 5)
{
if (i % 25 == 0)
{
CGContextSetLineWidth(context, 0.4);
// Draw a line
CGContextMoveToPoint(context, i, 0.0);
CGContextAddLineToPoint(context, i, width);
CGContextStrokePath(context);
CGContextSetLineWidth(context, 0.2);
}
else
{
// Draw a line
CGContextMoveToPoint(context, i, 0.0);
CGContextAddLineToPoint(context, i, width);
CGContextStrokePath(context);
}
}
for (i = 0; i < width; i += 5)
{
if (i % 25 == 0)
{
CGContextSetLineWidth(context, 0.4);
// Draw a line
CGContextMoveToPoint(context, 0.0, i);
CGContextAddLineToPoint(context, height, i);
CGContextStrokePath(context);
CGContextSetLineWidth(context, 0.2);
}
else
{
// Draw a line
CGContextMoveToPoint(context, 0.0, i);
CGContextAddLineToPoint(context, height, i);
CGContextStrokePath(context);
}
}
}
I am also setting up the UIScrollView and UIView as follows:
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
waveScrollView = [[WaveScrollView alloc] initWithFrame:frame];
CGRect waveframe = CGRectMake(0, 0, 25 * 5 * 10, (10 * 2 + 10) * 12);
EKGWaveView *ekgWaveView = [[EKGWaveView alloc] initWithFrame:waveframe];
waveScrollView.contentSize = CGSizeMake(waveframe.size.width, waveframe.size.height);
waveScrollView.maximumZoomScale = 4.0;
waveScrollView.minimumZoomScale = 0.75;
waveScrollView.clipsToBounds = YES;
waveScrollView.aView = ekgWaveView;
[waveScrollView addSubview:ekgWaveView];
waveScrollView.delegate = self;
[self.view addSubview:waveScrollView];
}
I appreciate any help. Thanks.
I'm pretty sure you've got some of your variables mixed up.
You're looping i from 0 to height but then you're using i as your x parameter when creating lines, and using width as your y parameter.