[Note: The code on the github example does not calculate the gradient on a pixel basis. The code on the github example calculates the gradient on a points basis. -Fattie] The code is working in pixels. First, it fills a simple raster bitmap buffer with the pixel color data. That obviously has no notion of … Read more
This is how I am getting a color from an image at a touch location. I translated this answer: https://stackoverflow.com/a/12579413/359578 (This sample does no error checking for nil) func createARGBBitmapContext(inImage: CGImage) -> CGContext { var bitmapByteCount = 0 var bitmapBytesPerRow = 0 //Get image width, height let pixelsWide = CGImageGetWidth(inImage) let pixelsHigh = CGImageGetHeight(inImage) // … Read more
Is this in Java? If so, you can use ImageIO.read( “yourImage.png” ) to get a BufferedImage. That will have a getData() method which will give you a Raster object, on which you can call getPixel. See link
CGContextFillRect(context, CGRectMake(x,y,1,1));
Create a canvas document.createElement Get the 2d context canvas.getContext(‘2d’) Draw the image to the canvas context.drawImage(image, x, y) Make sure the image is from the same domain or you won’t have access to its pixels Get the pixel data for the image context.getImageData(x1, y1, x2, y2) You want just the top left so context.getImageData(0, 0, … Read more
This is better than using getpixel all the time and works faster. import ImageGrab px = ImageGrab.grab().load() for y in range(0, 100, 10): for x in range(0, 100, 10): color = px[x, y] Reference: Image.load
import java.io.*; import java.awt.*; import javax.imageio.ImageIO; import java.awt.image.BufferedImage; public class GetPixelColor { public static void main(String args[]) throws IOException { File file = new File(“your_file.jpg”); BufferedImage image = ImageIO.read(file); // Getting pixel color by position x and y int clr = image.getRGB(x, y); int red = (clr & 0x00ff0000) >> 16; int green = (clr … Read more
To answer your question, you can more directly access a writable bitmap’s data by using the Lock, write, Unlock pattern, as demonstrated below, but it is typically not necessary unless you are basing your drawing upon the contents of the image. More typically, you can just create a new buffer and make it a bitmap, … Read more
In opencv 2.2, I’d use the C++ interface. cv::Mat in = /* your image goes here, assuming single-channel image with 8bits per pixel */ for(int row = 0; row < in.rows; ++row) { unsigned char* inp = in.ptr<unsigned char>(row); for (int col = 0; col < in.cols; ++col) { if (*inp++ == 0) { std::cout … Read more
Direct answer: This can only be done with OS-specific APIs. Some OSes do not allow changing pixels on the screen directly. On Windows, you can use pywin32 libraries to get screen’s device context with dc = GetDC(0) call, then paint pixels with SetPixel(dc, x, y, color). import win32gui import win32api dc = win32gui.GetDC(0) red = … Read more