TImageEnProc.Threshold

Declaration

procedure Threshold(DownLimit, UpLimit, DownVal, UpVal: TRGB); overload;
procedure Threshold(LoThreshold, HiThreshold: Integer; Red, Green, Blue: Boolean); overload;

Description

Replace colors above and below a threshold.
First overload assigns the DownVal color to all colors smaller or equal to DownLimit, and UpVal to all colors greater than UpLimit.
With second overload, you specify the low and high pixel value (LoThreshold and HiThreshold). Red, Green and Blue specify which channels to apply the threshold operation.

Note: Values are expected to be ordered. I.e. DownLimit.R should be less than UpLimit.R, DownLimit.G should be less than UpLimit.G, etc.

Note:
◼A UI for this is available to your users in the Image Processing dialog
◼If the image PixelFormat is not ie24RGB or ie32RGB, it will be converted

Demo

Demos\ImageEditing\EveryMethod\EveryMethod.dpr

Examples

// Load test image
ImageEnView1.IO.LoadFromFile( 'D:\TestImage.jpg' );

// Change all values less than R/G/B of 64 to black
ImageEnView1.Proc.Threshold( CreateRGB(64, 64, 64), CreateRGB(255, 255, 255), CreateRGB(0, 0, 0), CreateRGB(255, 255, 255) );

// Change all values greater than R/G/B of 192 to white
ImageEnView1.Proc.Threshold( CreateRGB(0, 0, 0), CreateRGB(192, 192, 192), CreateRGB(0, 0, 0), CreateRGB(255, 255, 255) );

// Change values with a red value greater than 192 to pure red
ImageEnView1.Proc.Threshold( CreateRGB(0, 0, 0), CreateRGB(192, 0, 0), CreateRGB(0, 0, 0), CreateRGB(255, 0, 0) );

TImageEnProc.Threshold