Convert png to high quality ico

Question

This may be a very simple problem, but I have not yet found the perfect solution. I am trying to convert png to ico with C # and found the question of converting .PNG to .ICO in C / C # , which seems to give a working solution, as shown below:

using (FileStream stream = File.OpenWrite(@"C:\temp\test.ico")) { Bitmap bitmap = (Bitmap)Image.FromFile(@"c:\temp\test.png"); Icon.FromHandle(bitmap.GetHicon()).Save(stream); } 

For my own project, I slightly modified this approach:

 string pngFile = "path/to/pngfile"; using (Bitmap bitmap = new Bitmap(pngFile)) { using (Icon icon = Icon.FromHandle(bitmap.GetHicon())) { using (MemoryStream stream = new MemoryStream()) { icon.Save(stream); // something interesting with icon here } } } 

The problem I am facing is that as a result ico is of poor quality, I assume that it has changed to 16x16 and lost some of the color, maybe now it has only 16 colors? How can I convert to a better ico file?

Answer 1

I believe that you will need a more reliable method than GetHIcon() . It is rather a "quick and dirty" option, and by no means lost.

Here is an example of a class that can preserve image quality on the path to conversion as an ICO:

https://gist.github.com/darkfall/1656050

Answer 2

Check http://www.codeproject.com/Tips/627823/Fast-and-high-quality-Bitmap-to-icon-converter This is a clear and fast solution for converting a raster image to png

Answer 3

In this question, the decision made uses imagemagick, which is an excellent image manipulation tool that allows you to control the size, color depth, etc. when converting from png to ico. I would really suggest trying this solution.

Using imagemagick will look something like this:

convert -resize x16 -gravity center -crop 16x16 + 0 + 0 input.png \ -flatten -colors 256 output / favicon.ico

(You can control -resize and -colors to achieve what you are looking for.)

The same options should be available programmatically in C # through http://imagemagick.codeplex.com