TImageEnView.LayersCreateFromEdge

Declaration

function LayersCreateFromEdge(x, y: integer; Tolerance: integer; MaxFilter: boolean = False; idx: Integer = -1): Integer;

Description

Creates a new Polyline layer with a closed polyline (polygon) along the edge of the background layer.
The edge is determined by simulating a flood fill starting at the point specified by x,y (which are bitmap or client area points depending on SelectionBase).
Tolerance specifies the color difference between the starting pixel and the pixel being tested (Range: 0 - 255).
Set MaxFilter to True to apply a maximum filter that removes noise.
idx specifies the insertion index for the layer, or -1 to append.
Result is the index of the created layer, or -1 if the method fails

Note: If SelectionBase = iesbClientArea then x and y are assumed to be visible points on the control. If iesbBitmap, the points specify a position on the bitmap.

Demos

	Demos\LayerEditing\MagicFillToPolygon\Magic2Polygon.dpr
	Demos\ImageEditing\EveryMethod\EveryMethod.dpr

Method Testing

ImageEnView1.IO.LoadFromFile( 'D:\TestImage.jpg' );

// Automatically select a color region and convert it to a polygon
ImageEnView1.SelectionBase := iesbBitmap;
if ImageEnView1.LayersCreateFromEdge( ClickPt.X, ClickPt.Y, 54, False ) > 0 then
begin
  ImageEnView1.CurrentLayer.BorderWidth := 2;
  ImageEnView1.CurrentLayer.BorderColor := Color;
  ImageEnView1.CurrentLayer.FillColor   := clWhite;
  ImageEnView1.LayersMergeAll();
end;

Examples

// Create a new polygon layer when the user clicks on the image
procedure TForm1.ImageEnView1MouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  ImageEnView1.SelectionBase := iesbClientArea;
  ImageEnView1.LayersCreateFromEdge( X, Y, 25, true );
  TIEPolyLineLayer( ImageEnView1.CurrentLayer ).LineColor := clBlack;
  TIEPolyLineLayer( ImageEnView1.CurrentLayer ).FillColor := clNone;
  ImageEnView1.Update();
end;

// Create a new polygon using a floodfill from the top left of the background image
ImageEnView1.SelectionBase := iesbClientArea;
ImageEnView1.LayersCreateFromEdge( ImageEnView1.XBmp2Scr( 0 ), ImageEnView1.YBmp2Scr( 0 ), 25, true);
TIEPolyLineLayer( ImageEnView1.CurrentLayer ).LineColor := clRed;
TIEPolyLineLayer( ImageEnView1.CurrentLayer ).LineWidth := 2;
TIEPolyLineLayer( ImageEnView1.CurrentLayer ).FillColor := clWhite;
TIEPolyLineLayer( ImageEnView1.CurrentLayer ).Transparency := 128; // 50% transparent
ImageEnView1.Update();

TImageEnView.LayersCreateFromEdge