Region checkpoints can be configured to pass even if the pixel colors in the actual image do not exactly match those in the expected (baseline) image. The maximum allowed difference between the colors is defined by the checkpoint’s Color Tolerance parameter. This is the value by which each RGB (red, green and blue) component of the same pixel in the actual and expected images may differ.

You receive this message if you specified a color tolerance value greater than 128, which allows more than a 50% difference between the RGB pixel values in the expected and actual images. High color tolerance values are ineffective when checking images, because they result in a broader range of colors being considered as identical, so the checkpoint can pass even if the compared images differ significantly. For example, the color tolerance of 128 instructs the checkpoint to consider the gray color (RGB 128, 128, 128) to be identical to any other color — black (RGB 0, 0, 0), white (RGB 255, 255, 255), blue (RGB 0, 0, 255), olive (RGB 128, 128, 0) and so on.

It is recommended that you minimize the color tolerance value to restrict pixel color matches to a few very similar colors only, and consider using other techniques to handle possible color differences. For example, you can provide an image comparison mask that specifies the image areas to be ignored by the checkpoint. Or, if the checked image contains transparency effects, you can capture the expected image retaining the alpha channel. To learn more about fine-tuning image comparisons in TestComplete, see How Image Comparison Works, Factors Affecting Image Comparison and Comparing and Finding Images - Specific Tasks

If you are sure you want to use the specified color tolerance value to handle possible color changes in the checked image, click Yes to ignore this warning. Otherwise, click No and review the checkpoint parameters.

Message - The specified Color Tolerance value allows a 50% or more difference between the pixel colors in the expected and actual images.

See Also