ImageEn, unit imageenproc

TImageEnProc.AddSoftShadow

TImageEnProc.AddSoftShadow


Declaration

procedure AddSoftShadow(Radius: Double = 4; Offset: Integer = 4; Position: TIEShadowPosition = iespBottomLeft; AdaptSize: Boolean = true; ShadowColor: TColor = clBlack; Intensity: Integer = 100; BGAlphaThreshold: Integer = 128); overload;
procedure AddSoftShadow(Radius : Double; OffsetX : Integer; OffsetY : Integer; AdaptSize : Boolean = true; ShadowColor: TColor = clBlack; Intensity : Integer = 100; BGAlphaThreshold: Integer = 128); overload;


Description

Add a soft shadow (Gaussian Shadow) or glow to the image. The image's alpha channel is used for the shadow effect (it will be added if it does not exist).



Parameter Description
Radius The width of the shadow
Offset The offset from the image of the shadow
Position Where the shadow is drawn (see below). iespBottomRight is typical
AdaptSize If enabled (default) then the dimensions of your image will be enlarged so that the content does not change when the shadow is added (You can use IESoftShadowSize to calculate how much larger the image will become)
ShadowColor Color of the shadow (default is clBlack)
Intensity The shadow intensity in the range of 0 and 100 (default is 100)
BGAlphaThreshold The alpha threshold used to separate foreground and background pixels in the range 0 to 255 (default is 128). A low value may show color artifacts where anti-aliased curves merge with the shadow. A value too high will lessen the anti-aliasing of curves (making them look blocky).

Shadow Position
Value Description
iespTopLeft Draw on top and left (as if sun is at bottom-right of image)
iespTopRight Draw on top and right (as if sun is at bottom-left of image
iespBottomLeft Draw on bottom and left (as if sun is at top-right of image)
iespBottomRight Draw on bottom and right (as if sun is at top-left of image)
iespAll "Glow": Shadow is drawn on all sides of image
iespInner Inner Shadow: Same as calling AddInnerShadow

Notes:
- The effect will not be visible unless EnableAlphaChannel = True
- Alternatively you can specifiy separate offset values for the position of the shadow. Positive values make the shadow appear on the right/bottom, whereas negative values place it at the left/top. Values of zero give the image a "Glow" effect
- A UI for this is available to your users in the Image Processing dialog


Demos

Demo  Demos\ImageEditing\SoftShadow\SoftShadow.dpr
Demo  Demos\ImageEditing\EveryMethod\EveryMethod.dpr


Examples

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

  

// Add a shadow to the bottom-right of the image
ImageEnView1.Proc.AddSoftShadow( 5, 4, iespBottomRight );

  

// Add a yellow glow to the image
ImageEnView1.Proc.AddSoftShadow( 5, 0, iespAll, True, clYellow );

  


// Add a shadow to the top-left of the image
ImageEnView1.Proc.AddSoftShadow( 5, -4, -4 );
// Or....
ImageEnView1.Proc.AddSoftShadow( 5, 4, iespTopLeft );

// Add a soft shadow to image in a TBitmap
blurRad := 5;
offset := 4;
ie := TImageEnView.Create(nil);
try
  ie.Background := clWhite;
  ie.Bitmap.assign( MyBitmap );
  ie.update;
  ie.Proc.AddSoftShadow( blurRad, offset, iespBottomRight, True, cShadowColor );
  ie.RemoveAlphaChannel( True );
  MyBitmap.assign( ie.bitmap );
finally
  ie.Free;
end;