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I am trying to create a HeatMap witch is displayed in an ImageView in my Android application.

I get the data as an .csv file and write it to an multidimensional array. The Array contains data (0 to 499)for each Pixel of a 100x400 Image. I created an java class to get a colour gradient array from 5 colours and get back an (int) Array[500] with the sRGB colors. Now I am stuck on how to create a Bitmap (or something like that) with the data and the corresponding Colour from the Array. Tried to understand the GoogleMaps Heatmap example and other ones but have no clue yet. I am sorry if I asked an existing Question, but i have found nothing helpful yet. The code below is written in java and works with java libs (like java.awt.image.BufferedImage) witch are not accessible for Android. dataColorIndices is an 100x400 Array witch contains the specific indice for the colour Array of each pixel in Data and is created in another method.

private void drawData() 
{
    bufferedImage = new BufferedImage(data.length,data[0].length, BufferedImage.TYPE_INT_ARGB);
    bufferedGraphics = bufferedImage.createGraphics();
    
    for (int x = 0; x < data.length; x++)
    {
        for (int y = 0; y < data[0].length; y++)
        {
            bufferedGraphics.setColor(colors[dataColorIndices[x][y]]);
            bufferedGraphics.fillRect(x, y, 1, 1);
        }
    }
    try {
        File outputfile = new File("C:/.../HeatMap.png");
        ImageIO.write(bufferedImage, "png", outputfile);
    } catch (IOException e) {
        // handle exception;
    }
}

The Code is written by Matthew Beckler (https://www.mbeckler.org/heatMap/).

Louis Gouderwis
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    It would be helpful to post some code for us to see what you have already or what you have tried – Oozeerally Oct 20 '20 at 15:46
  • Would it be easier to use a library like JFreeChart? https://stackoverflow.com/questions/10739422/heatmaps-with-jfreechart – Rob Evans Oct 21 '20 at 09:47

0 Answers0