TransparentColor Property

Summary

Gets or sets the transparent color used when painting this image.

Syntax

Objective-C

C++

Java

public RasterColor TransparentColor { get; set; }

Public Property TransparentColor As RasterColor

@property (nonatomic, copy) LTRasterColor *transparentColor

public RasterColor getTransparentColor() 
public void setTransparentColor(RasterColor value)

public: 
property RasterColor TransparentColor { 
   RasterColor get(); 
   void set (    RasterColor ); 
}

Property Value

The transparent color used when painting this image.

Remarks

The TransparentColor of a RasterImage is used when the Transparent property value is set to true.

Note, transparent paint does not work with RasterPaintEngine.Gdi. For more information, refer to RasterPaintProperties.

If this RasterImage has a BitsPerPixel value of 8 or less, then the image has a palette. For palettized images, the value of the TransparentColor can be an RGB value or a palette index.

To set a palette index as the transparent color, use the RasterColor.FromPaletteIndex method.

If the color passed is a true RGB value(The value of see RasterColor.IsPaletteIndex is false and the image has a palette, then this RasterImage object will call GetTrueColorValue on the TransparentColor to translate it into the nearest palette index entry before using it to determine the actual transparent color in the image when painting.

For more information, refer to PNG Files and Transparency.

Example

For an example of how to use this property when loading/saving images with transparent colors such as GIF, refer to GetTrueColorValue.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Dicom; 
using Leadtools.Drawing; 
using Leadtools.Controls; 
using Leadtools.Svg; 
 
 
public void TransparentColorExample() 
{ 
	RasterCodecs codecs = new RasterCodecs(); 
 
	string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif"); 
	string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1_Transparent.gif"); 
 
	// Load the image 
	RasterImage image = codecs.Load(srcFileName); 
 
	// Change the image's palette to be Red and Blue 
	RasterColor[] redBluePalette = new RasterColor[2]; 
	redBluePalette[0] = RasterColor.FromKnownColor(RasterKnownColor.Red); 
	redBluePalette[1] = RasterColor.FromKnownColor(RasterKnownColor.Blue); 
	image.SetPalette(redBluePalette, 0, 2); 
 
	// make red the transparent color 
	image.Transparent = true; 
	image.TransparentColor = redBluePalette[0]; 
 
	// Save the image 
	codecs.Save(image, destFileName, RasterImageFormat.Gif, 8); 
 
	// Now load Ocr1_Transparent.gif in Internet Explorer. 
	// Notice how red is treated as a transparent color. 
	// You should get Blue text on a white background 
	//    (if IE's background color is white). 
 
	image.Dispose(); 
	codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS21\Resources\Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Core 
Imports Leadtools.ImageProcessing.Color 
Imports Leadtools.Controls 
Imports Leadtools.Dicom 
Imports Leadtools.Drawing 
Imports Leadtools.Svg 
 
Public Sub TransparentColorExample() 
   Dim codecs As RasterCodecs = New RasterCodecs() 
 
   Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif") 
   Dim destFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1_Transparent.gif") 
 
   ' Load the image 
   Dim image As RasterImage = codecs.Load(srcFileName) 
 
   ' Change the image's palette to be Red and Blue 
   Dim redBluePalette As RasterColor() = New RasterColor(1) {} 
   redBluePalette(0) = RasterColor.FromKnownColor(RasterKnownColor.Red) 
   redBluePalette(1) = RasterColor.FromKnownColor(RasterKnownColor.Blue) 
   image.SetPalette(redBluePalette, 0, 2) 
 
   ' make red the transparent color 
   image.Transparent = True 
   image.TransparentColor = redBluePalette(0) 
 
   ' Save the image 
   codecs.Save(image, destFileName, RasterImageFormat.Gif, 8) 
 
   ' Now load Ocr1_Transparent.gif in Internet Explorer. 
   ' Notice how red is treated as a transparent color. 
   ' You should get Blue text on a white background 
   '    (if IE's background color is white). 
 
   image.Dispose() 
   codecs.Dispose() 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\LEADTOOLS21\Resources\Images" 
End Class

Requirements

Target Platforms

Reference

RasterImage Class

RasterImage Members

Download our FREE evaluation

Help Version 21.0.2021.7.2

Leadtools Assembly

Introduction

Getting Started

Namespaces

Leadtools Namespace

Leadtools.ImageProcessing Namespace

Assemblies