Paul Maddox: November 2008

Monday, November 17, 2008

C# .NET Image Manipulation Resize + Grayscale + TIFF

Code from the last three posts can be downloaded formatted properly here:

http://paulmaddox.net/BlogFiles/ImageManipulation_Program.cs.txt

Note you need to add the System.Drawing reference in order to get it to work with a new project.

# posted by Paul Maddox @ 1:21 PM 0 Comments

Convert C# .NET Bitmap to grayscale

Here's some code to convert a Bitmap into grayscale using luminance. Note, this does not change the color depth, rather it sets the pixels to grey within a 24bit color space.

private static Bitmap ToGrayscale(Bitmap bmIn)
{
Bitmap bmOut = new Bitmap(bmIn.Width, bmIn.Height, PixelFormat.Format24bppRgb);

for (int x = 0; x < bmIn.Width; x++)
{
  for (int y = 0; y < bmIn.Height; y++)
  {
   Color px = bmIn.GetPixel(x, y);

   int luminance = (int)((0.3f * px.R) + (0.59 * px.G) + (0.11 * px.B));

   bmOut.SetPixel(x, y, Color.FromArgb(luminance, luminance, luminance));
  }
}

return bmOut;
}

# posted by Paul Maddox @ 1:10 PM 0 Comments

C# .NET reading a bitmap, resizing / rescaling and saving as a TIFF

Here's some code to read in a bitmap and save a new bitmap at a quarter of the size. Note. a boilerplate method is needed to get the encoder for the write format. This makes it easy to change from TIFF to JPEG, PNG, etc.

// Load the bitmap from first argument filename
Bitmap bmIn = new Bitmap(inputFilename);

// Create a new bitmap from the first, scaling down as we go
Bitmap bmOut = new Bitmap(bmIn, new Size(bmIn.Width/2, bmIn.Height/2));

// Create an parameter set that we use to save the file
EncoderParameters encParams = new EncoderParameters(3);

// Set some parameters
encParams.Param[0] = new EncoderParameter(Encoder.ColorDepth, 24L);
encParams.Param[1] = new EncoderParameter(Encoder.Compression, (long)EncoderValue.CompressionNone);
encParams.Param[2] = new EncoderParameter(Encoder.SaveFlag, (long)EncoderValue.MultiFrame);

// Save bitmap to second argument filename
bmOut2.Save(outputFilename, GetEncoder(ImageFormat.Tiff), encParams);
private static ImageCodecInfo GetEncoder(ImageFormat format)
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();

foreach (ImageCodecInfo codec in codecs)
{
if (codec.FormatID == format.Guid)
{
return codec;
}
}
return null;
}

# posted by Paul Maddox @ 1:04 PM 0 Comments

Out of Memory / OutOfMemoryException on Graphics.FromImage with PixelFormat.Format16bppArgb1555 or PixelFormat.Format16bppGrayScale

If you have some code like this:

Bitmap bmp = new Bitmap(100,100, PixelFormat.Format16bppArgb1555);
Graphics gfx = Graphics.FromImage(bmp);

You will find you get an out of memory exception upon executing the code. The reason? .NET does not actually support Format16bppArgb1555 or PixelFormat.Format16bppGrayScale.

# posted by Paul Maddox @ 12:52 PM 0 Comments

Wednesday, November 5, 2008

Visual Studio Errors

Thanks to Matt at Siemens for this one.

"If you get similar errors to below then deleting everything in the C:\Documents and Settings\\Local Settings\Application Data\Microsoft\VisualStudio\\ProjectAssemblies will solve this. Do not delete anything above this directory as you will lose all your toolbars and settings."

Error 4 The "ResolveAssemblyReference" task failed unexpectedly.

System.IO.IOException: Incorrect function.

at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)

at System.IO.Directory.InternalGetFileDirectoryNames(String path, String userPathOriginal, String searchPattern, Boolean includeFiles, Boolean includeDirs, SearchOption searchOption)

at System.IO.Directory.GetDirectories(String path, String searchPattern, SearchOption searchOption)

at System.IO.Directory.GetDirectories(String path, String searchPattern)

at Microsoft.Build.Tasks.SystemState.GetDirectories(String path, String pattern)

at Microsoft.Build.Tasks.ReferenceTable.FindSatellites(Reference reference)

at Microsoft.Build.Tasks.ReferenceTable.FindAssociatedFiles()

at Microsoft.Build.Tasks.ReferenceTable.ComputeClosure()

at Microsoft.Build.Tasks.ReferenceTable.ComputeClosure(DependentAssembly[] remappedAssembliesValue, ITaskItem[] referenceAssemblyFiles, ITaskItem[] referenceAssemblyNames, ArrayList exceptions)

at Microsoft.Build.Tasks.ResolveAssemblyReference.Execute(FileExists fileExists, DirectoryExists directoryExists, GetDirectories getDirectories, GetAssemblyName getAssemblyName, GetAssemblyMetadata getAssemblyMetadata, GetRegistrySubKeyNames getRegistrySubKeyNames, GetRegistrySubKeyDefaultValue getRegistrySubKeyDefaultValue, GetLastWriteTime getLastWriteTime)

at Microsoft.Build.Tasks.ResolveAssemblyReference.Execute()

at Microsoft.Build.BuildEngine.TaskEngine.ExecuteInstantiatedTask(EngineProxy engineProxy, ItemBucket bucket, TaskExecutionMode howToExecuteTask, ITask task, Boolean& taskResult) MyProject

# posted by Paul Maddox @ 4:45 AM 0 Comments

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