TImageEnProc.CastColor

Declaration

procedure CastColor(BmpX, BmpY: Integer; NewColor: TRGB; Tolerance: Integer; SampleSize: Integer = 1; MaxFilter: Boolean = False; NewAlpha: Integer = -1); overload;
procedure CastColor(BmpX, BmpY: Integer; NewColor: TColor; Tolerance: Integer; SampleSize: Integer = 1; MaxFilter: Boolean = False; NewAlpha: Integer = -1); overload;

Description

Perform a flood-fill starting at the bitmap coordinates x, y, i.e. replacing all encountered pixels that match the color at the starting position with NewColor.

Parameter	Description
BmpX, BmpY	Pixel specifying the color to be replaced
NewColor	Replacement color (if clNone, then the new color is not set)
Tolerance	The maximum difference from the starting pixel (0 to 255, where 0 requires an exact color match, whereas 255 would match every color)
SampleSize	The diameter of the area to sample (centered on BmpX, BmpY) to determine the seed color. If 1 is specified (Default) only the color of the specified pixel is used
MaxFilter	Apply a maximum filter for more aggressive color selection (remove the "black hole")
NewAlpha	Alpha value for any set colors, e.g. 255 to make all colored pixels fully opaque. Specify -1 to ignore the alpha channel

Note:
◼ To cast all pixels in the image, instead of flooding, use CastColorRange
◼ To flood fill an area with transparency, use CastAlpha
◼ If the image PixelFormat is not ie24RGB or ie32RGB, it will be converted

CastColor vs CastAlpha

These methods can be used interchangeably.

// These two methods have the same effect (Flood filling Red)...
ImageEnView1.Proc.CastColor( x, y, clRed { NewColor }, 0, 1, False, -1 { NewAlpha } );
ImageEnView1.Proc.CastAlpha( x, y, -1 { NewAlpha }, 0, 1, False, clRed { NewColor } );

// These two methods have the same effect (Flood filling alpha to 125)...
ImageEnView1.Proc.CastColor( x, y, clNone { NewColor }, 0, 1, False, 125 { NewAlpha } );
ImageEnView1.Proc.CastAlpha( x, y, 125 { NewAlpha }, 0, 1, False, clNone { NewColor } );

// These two methods have the same effect (Flood filling Red with alpha of 255)...
ImageEnView1.Proc.CastColor( x, y, clRed { NewColor }, 0, 1, False, 255 { NewAlpha } );
ImageEnView1.Proc.CastAlpha( x, y, 255 { NewAlpha }, 0, 1, False, clRed { NewColor } );

Demo

Demos\ImageEditing\EveryMethod\EveryMethod.dpr

Examples

// Perform a red flood fill starting at 0,0 (with a tolerance of 10)
ImageEnView1.Proc.CastColor( 0, 0, clRed, 10 );

// When user clicks image, flood fill pixels of a similar color to white
procedure TForm1.ImageEnView1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
if fColorCasting then
ImageEnView1.Proc.CastColor( ImageEnView1.XScr2Bmp(x), ImageEnView1.YScr2Bmp(y), CreateRGB(255, 255, 255), 10 );
end;

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

// Perform a red flood fill starting at 0,0 (with a tolerance of 10)
ImageEnView1.Proc.CastColor( 0, 0, clRed, 10 );

TImageEnProc.CastColor