TransparentColor Property

Summary

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

Syntax

Objective-C

C++/CLI

Java

Python

public RasterColor TransparentColor { get; set; }

@property (nonatomic, copy) LTRasterColor *transparentColor

public RasterColor getTransparentColor(); 
public void setTransparentColor( 
   RasterColor rasterColor 
);

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

TransparentColor # get and set (RasterImage)

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

Java

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:\LEADTOOLS23\Resources\Images"; 
}

 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.util.ArrayList; 
import java.util.List; 
 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
 
import leadtools.*; 
import leadtools.codecs.*; 
import leadtools.imageprocessing.core.*; 
import leadtools.svg.*; 
import leadtools.imageprocessing.CloneCommand; 
import leadtools.imageprocessing.FillCommand; 
import leadtools.imageprocessing.FlipCommand; 
import leadtools.imageprocessing.GrayscaleCommand; 
import leadtools.imageprocessing.color.InvertCommand; 
import leadtools.imageprocessing.color.PosterizeCommand; 
 
 
public void transparentColorExample() { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   RasterCodecs codecs = new RasterCodecs(); 
   String srcFileName = combine(LEAD_VARS_IMAGES_DIR, "Ocr1.tif"); 
   String destFileName = combine(LEAD_VARS_IMAGES_DIR, "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); 
   assertTrue(redBluePalette[0].equals(RasterColor.fromKnownColor(RasterKnownColor.RED))); 
 
   // Make red the transparent color 
   image.setTransparent(true); 
   image.setTransparentColor(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). 
 
   // Clean up 
   image.dispose(); 
   codecs.dispose(); 
 
   assertTrue("file unsuccessfully saved to " + destFileName, (new File(destFileName)).exists()); 
   System.out.printf("File saved successfully to %s%n", destFileName); 
}

Requirements

Target Platforms

Reference

RasterImage Class

RasterImage Members

Download our FREE evaluation

Help Version 23.0.2024.5.22