I have an image with a bright center but dark edges. I need to draw rectangle at a certain brightness, so that the darker areas remain outside. Or get the coordinates of this frame. Preferably using OpenCV, the programming language is not important.
i want to blur Whole image and display circle or rectangle area on image.
with move the circle and rectangle on image.save the blur image without circle and rectangle.
Is there a way to dynamically draw a dithered gradient on iOS? I'm currently using CGContextDrawLinearGradient, but it produces a noticeable banding effect.
I have logo text drawn as shapes (closed CGBezierPaths) that I want to fill with a gradient.(Light at the top, moving to dark at the bottom) How can I fill each shape with gradient such that the gradient is the same color for each shape.
The problem is drawing the gradient for each shape, if the letters are different height then the gradient has a different ramp since the distance is smaller. Hope that makes sense.
So basically I want draw a single gradient down the rect and use all the shapes as a clipping mask. Is this possible?
For gradient drawing - take a look at this project:
https://github.com/wczekalski/CDPieMenu
It creates gradient using two colors programmatically.
I would like to use UIBezierPath to create a polygon shape with rounded corners. I believe this will be possible using addCurveToPoint:controlPoint1:controlPoint2: and similar code to that found in http://www.codeproject.com/Articles/31859/Draw-a-Smooth-Curve-through-a-Set-of-2D-Points-wit, but I was wondering if there's any existing (or better) way to achieve this?
I should point out that this will need to be for any convex polygon (such as found in a voronoi diagram) and not just a rectangular shape.
You don't want addCurveToPoint. If you're using UIBezierPath, you want addArcWithCenter:radius:startAngle:endAngle:clockwise:
Here's what you do. Draw your rectangle. Figure out the corner radius you want. Draw circles in each corner, inset from each side by your corner radius. (the center of each corner circle will be inset from each corner by the corner radius in both x and y.) Then map out a sequence of 4 lines, connecting the points where your rectangle touches the circles in each corner.
Each arc will cover 90 degrees (pi/2, in radians.) The top right corner's are will range from 0 to pi/2. The top left corner's angle will start at pi/2 and go to pi. the bottom left corner's arc will range from pi to 3/2 pi. The bottom right arc's angle will range from 3/2 pi to 2pi.
You'll use a sequence of:
moveToPoint addLineToPoint -- first side
addArcWithCenter:radius:startAngle:endAngle:clockwise -- first
rounded corner
lineToPoint --second side, to beginning of next rounded corner
addArcWithCenter:radius:startAngle:endAngle:clockwise -- second
rounded corner
lineToPoint --third side, to beginning of next rounded corner
addArcWithCenter:radius:startAngle:endAngle:clockwise -- third
rounded corner
lineToPoint --forth side, to beginning of last
rounded corner
addArcWithCenter:radius:startAngle:endAngle:clockwise-- forth rounded
corner, connecting back to first side.
closePath
You can use PaintCodeApp so you don't have to write any of the drawing code. There's a demo download available: http://www.paintcodeapp.com/
You can refer below link to create a polygon shape with rounded corners.
http://www.scriptscoop.net/t/ec0f886dcfea/create-hexagon-imageview-shape-in-ios.html