Syntax
Parameters
buffer
The original image buffer in memory as System.IntPtr array. The image format in memory should be one of the following supported formats:
- RasterImageFormat.Jpeg, Bits per pixel: 8 for grayscale, 24 for color.
- RasterImageFormat.Jpeg411, Bits per pixel: 8 for grayscale, 24 for color.
- RasterImageFormat.Jpeg422, Bits per pixel: 8 for grayscale, 24 for color.
- RasterImageFormat.ExifJpeg411, Bits per pixel: 24 (color only).
- RasterImageFormat.ExifJpeg422, Bits per pixel: 24 (color only).
- RasterImageFormat.Gif, Bits per pixel: 1, 2, 3, 4, 5, 6, 7, and 8.
- RasterImageFormat.Png, Bits per pixel: 1, 4, 8, 24, 32, 48, and 64.
- RasterImageFormat.Bmp, Bits per pixel: 1, 4, 8, 16, 24, and 32.
- RasterImageFormat.BmpRle, Bits per pixel: 4, and 8.
length
The size, in bytes, of the buffer parameter in memory.
options
The options used in the optimization process.
progressCallback
Optional callback function that provides information about the progress of the optimization process.
Return Value
A Leadtools.RasterNativeBuffer structure that contains the image optimized buffer in memory.
Example
This example will optimize a Png image file and then save it to a separate folder
Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageOptimization
Imports Leadtools.Support.Examples
<TestMethod()> _
Public Sub TestPngImageOptimizer()
' Initialize the RasterCodecs class
Dim Codecs As RasterCodecs = New RasterCodecs()
' The input and output location
Dim inputFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "LittleGFlyingAlpha.png")
Dim outputFolder As String = Path.Combine(LEAD_VARS.ImagesDir, "OptimizedImages")
' Initialize a new Optimizer object
Dim optimizer As ImageOptimizer = New ImageOptimizer()
' Optimization Options
Dim options As ImageOptimizerOptions = ImageOptimizerOptions.Default
'' Set custom optimization options
options.Distance = 20
options.Percent = 15
options.PngQualityFactor = 4
Dim bufferPtr As IntPtr
Dim bufferSize As Integer = 0
LoadFileIntoPointer(inputFileName, bufferPtr, bufferSize)
If (IntPtr.Zero <> bufferPtr AndAlso bufferSize > 0) Then
Dim optBuffer As RasterNativeBuffer = optimizer.OptimizeBuffer(Codecs, bufferPtr, bufferSize, options, Nothing)
' Free orgBuffer.PointerBuffer, since it won't be needed anymore.
Marshal.FreeHGlobal(bufferPtr)
' Save this image into the output folder
' Make sure the output folder exists
If (Not Directory.Exists(outputFolder)) Then
Directory.CreateDirectory(outputFolder)
End If
' Get the name of the output file from the input file
Dim outputFileName As String = Path.Combine(outputFolder, Path.GetFileName(inputFileName))
' Save the optimized buffer to the output file
Using fs As FileStream = File.Create(outputFileName)
Dim optArray(CInt(optBuffer.Length)) As Byte
Marshal.Copy(optBuffer.Data, optArray, 0, optArray.Length)
fs.Write(optArray, 0, optArray.Length)
End Using
' Free optBuffer.PointerBuffer, since it won't be needed anymore.
Marshal.FreeHGlobal(optBuffer.Data)
' Compare the original image size with the optimized size.
Dim orgSize As Long = New FileInfo(inputFileName).Length
Dim optSize As Long = New FileInfo(outputFileName).Length
Dim percentage As Integer = CType(CType(optSize * 100.0 / orgSize, Double), Integer)
Dim message As String = String.Format( _
"Original image size: {0} KB{1}Optimized image size: {2} KB{1}Percentage: {3}%", _
orgSize / 1024, Environment.NewLine, optSize / 1024, _
100 - percentage)
Console.WriteLine(message)
End If
'shutdown the RasterCodecs class.
End Sub
' This method opens an image file and loads it into IntPtr.
Private Sub LoadFileIntoPointer(ByVal fileName As String, ByRef ptr As IntPtr, ByRef size As Integer)
Using fs As FileStream = File.OpenRead(fileName)
' Allocate memory to load the file
size = CType(fs.Length, Integer)
ptr = Marshal.AllocHGlobal(size)
' Load in 32K chunks
Const bufferSize As Integer = 32 * 1024
Dim buffer(bufferSize) As Byte
Dim bytesToRead As Integer
Dim bytesLeft As Integer = CType(fs.Length, Integer)
Dim tempPtr As IntPtr = ptr ' where we are
Do
' read a chunk
bytesToRead = Math.Min(bufferSize, bytesLeft)
If (bytesToRead > 0) Then
fs.Read(buffer, 0, bytesToRead)
' copy into our buffer
Marshal.Copy(buffer, 0, tempPtr, bytesToRead)
' move the temp pointer
tempPtr = New IntPtr(tempPtr.ToInt64() + bytesToRead)
bytesLeft -= bytesToRead
End If
Loop While (bytesToRead > 0)
End Using
End Sub
Public NotInheritable Class LEAD_VARS
Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageOptimization;
public void TestPngImageOptimizer( )
{
// Initialize the RasterCodecs class
RasterCodecs codecs = new RasterCodecs();
// The input and output location
string inputFileName = Path.Combine(LEAD_VARS.ImagesDir, "LittleGFlyingAlpha.png");
string outputFolder = Path.Combine(LEAD_VARS.ImagesDir, "OptimizedImages");
// Initialize a new Optimizer object
ImageOptimizer optimizer = new ImageOptimizer();
// Optimization Options
ImageOptimizerOptions options = ImageOptimizerOptions.Default;
// Set custom optimization options
options.Distance = 20;
options.Percent = 15;
options.PngQualityFactor = 4;
IntPtr bufferPtr;
int bufferSize = 0;
LoadFileIntoPointer(inputFileName, out bufferPtr, out bufferSize);
if(IntPtr.Zero != bufferPtr && bufferSize > 0)
{
RasterNativeBuffer optBuffer = optimizer.OptimizeBuffer(codecs, bufferPtr, bufferSize, options, null);
// Free orgBuffer.PointerBuffer, since it won't be needed anymore.
Marshal.FreeHGlobal(bufferPtr);
// Save this image into the output folder
// Make sure the output folder exists
if(!Directory.Exists(outputFolder))
Directory.CreateDirectory(outputFolder);
// Get the name of the output file from the input file
string outputFileName = Path.Combine(outputFolder, Path.GetFileName(inputFileName));
// Save the optimized buffer to the output file
using(FileStream fs = File.Create(outputFileName))
{
byte[] optArray = new byte[optBuffer.Length];
Marshal.Copy(optBuffer.Data, optArray, 0, optArray.Length);
fs.Write(optArray, 0, optArray.Length);
}
// Free optBuffer.PointerBuffer, since it won't be needed anymore.
Marshal.FreeHGlobal(optBuffer.Data);
// Compare the original image size with the optimized size.
long orgSize = new FileInfo(inputFileName).Length;
long optSize = new FileInfo(outputFileName).Length;
int percentage = (int)((double)optSize * 100.0 / orgSize);
string message = string.Format(
"Original image size: {0} KB{1}Optimized image size: {2} KB{1}Percentage: {3}%",
orgSize / 1024, Environment.NewLine, optSize / 1024,
100 - percentage);
MessageBox.Show(message);
}
//shutdown the RasterCodecs class.
}
// This method opens an image file and loads it into IntPtr.
private void LoadFileIntoPointer(string fileName, out IntPtr ptr, out int size)
{
using(FileStream fs = File.OpenRead(fileName))
{
// Allocate memory to load the file
size = (int)fs.Length;
ptr = Marshal.AllocHGlobal(size);
// Load in 32K chunks
const int bufferSize = 32 * 1024;
byte[] buffer = new byte[bufferSize];
int bytesToRead;
int bytesLeft = (int)fs.Length;
IntPtr tempPtr = ptr; // where we are
do
{
// read a chunk
bytesToRead = Math.Min(bufferSize, bytesLeft);
if(bytesToRead > 0)
{
fs.Read(buffer, 0, bytesToRead);
// copy into our buffer
Marshal.Copy(buffer, 0, tempPtr, bytesToRead);
// move the temp pointer
tempPtr = new IntPtr(tempPtr.ToInt64() + bytesToRead);
bytesLeft -= bytesToRead;
}
}
while(bytesToRead > 0);
}
}
static class LEAD_VARS
{
public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
