Leadtools Namespace > RasterImage Class : TransparentColor Property |
public RasterColor TransparentColor {get; set;}
'Declaration Public Property TransparentColor As RasterColor
'Usage Dim instance As RasterImage Dim value As RasterColor instance.TransparentColor = value value = instance.TransparentColor
public RasterColor TransparentColor {get; set;}
get_TransparentColor();
set_TransparentColor(value);
public: property RasterColor TransparentColor { RasterColor get(); void set ( RasterColor value); }
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 Leadtools.Drawing.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.
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:\Users\Public\Documents\LEADTOOLS Images" End Class
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:\Users\Public\Documents\LEADTOOLS Images"; }
RasterImageExamples.prototype.TransparentColorExample = function ( ) { Tools.SetLicense ( ) ; with (Leadtools) { with (Leadtools.Codecs) { var codecs = new RasterCodecs(); var srcFileName = "Assets\\Ocr1.tif"; var destFileName = "Ocr1_Transparent.gif"; var image; // Load the image return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) { return codecs.loadAsync(LeadStreamFactory.create(loadFile)) }) .then(function (img) { image = img; // Change the image's palette to be Red and Blue var redBluePalette = [RasterColorHelper.fromKnownColor(RasterKnownColor.Red), RasterColorHelper.fromKnownColor(RasterKnownColor.Blue)]; image.setPalette(redBluePalette, 0, 2); // make red the transparent color image.transparent = true; image.transparentColor = redBluePalette[0]; // Save the image return Tools.AppLocalFolder().createFileAsync(destFileName) }) .then(function (saveFile) { var saveStream = LeadStreamFactory.create (saveFile); return codecs.saveAsync(image, saveStream, RasterImageFormat.gif, 8) }) .then(function () { // 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.close(); codecs.close(); }) } } }
[TestMethod] public async Task TransparentColorExample() { RasterCodecs codecs = new RasterCodecs(); string srcFileName = @"Assets\Ocr1.tif"; string destFileName = @"Ocr1_Transparent.gif"; // Load the image StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName); RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile)); // Change the image's palette to be Red and Blue RasterColor[] redBluePalette = { RasterColorHelper.FromKnownColor(RasterKnownColor.Red), RasterColorHelper.FromKnownColor(RasterKnownColor.Blue)}; image.SetPalette(redBluePalette, 0, 2); // make red the transparent color image.Transparent = true; image.TransparentColor = redBluePalette[0]; // Save the image StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(destFileName); ILeadStream saveStream = LeadStreamFactory.Create(saveFile); await codecs.SaveAsync(image, saveStream, 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(); }
public void TransparentColorExample(RasterImage image, Stream destStream) { // Change the image's palette to be Red and Blue RasterColor[] redBluePalette = new RasterColor[2]; redBluePalette[0] = RasterColorConverter.FromColor(Colors.Red); redBluePalette[1] = RasterColorConverter.FromColor(Colors.Blue); image.SetPalette(redBluePalette, 0, 2); // make red the transparent color image.Transparent = true; image.TransparentColor = redBluePalette[0]; // Save the image RasterCodecs codecs = new RasterCodecs(); codecs.Save(image, destStream, 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(); }
Public Sub TransparentColorExample(ByVal image As RasterImage, ByVal destStream As Stream)
' Change the image's palette to be Red and Blue
Dim redBluePalette As RasterColor() = New RasterColor(1){}
redBluePalette(0) = RasterColorConverter.FromColor(Colors.Red)
redBluePalette(1) = RasterColorConverter.FromColor(Colors.Blue)
image.SetPalette(redBluePalette, 0, 2)
' make red the transparent color
image.Transparent = True
image.TransparentColor = redBluePalette(0)
' Save the image
Dim codecs As RasterCodecs = New RasterCodecs()
codecs.Save(image, destStream, 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()
End Sub
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2