Anyone know whats this problem?
I got this warning Field xxx is never assigned to, and will always have its default value null on private static Quantizer quantit;
I dont know what to do to fix, cause when I try to use quantit.Quantize() debug says: "Object reference not set to an instance of an object." and point to au = quantit.Quantize();
The code:
public class Quantization : System.Windows.Forms.Form
{
private static Quantizer quantit;
private Button btnLoad;
private PictureBox imgPhoto;
public Quantization()
{
btnLoad = new Button();
btnLoad.Text = "&Load";
btnLoad.Left = 10;
btnLoad.Top = 10;
btnLoad.Click += new System.EventHandler(this.OnLoadClick);
imgPhoto = new PictureBox();
imgPhoto.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
imgPhoto.Width = this.Width / 2;
imgPhoto.Height = this.Height / 2;
imgPhoto.Left = (this.Width - imgPhoto.Width) / 2;
imgPhoto.Top = (this.Height - imgPhoto.Height) / 2;
imgPhoto.SizeMode = PictureBoxSizeMode.StretchImage;
this.Controls.Add(btnLoad);
this.Controls.Add(imgPhoto);
}
protected void OnLoadClick(object sender, System.EventArgs e)
{
OpenFileDialog dlg = new OpenFileDialog();
dlg.Title = "Open Image";
dlg.Filter = "jpg files (*.jpg)|*.jpg|All files (*.*)|*.*" ;
if (dlg.ShowDialog() == DialogResult.OK)
{
Bitmap au;
//Image bmp = Image.FromFile("D:\Documents and Settings\kiosk.suprisul\My Documents\foto1.jpg");
au = quantit.Quantize();
imgPhoto.Image = au;
//imgPhoto.Image = bmp;
//imgPhoto.Image = au;
//new Bitmap(dlg.OpenFile());
}
dlg.Dispose();
}
[STAThread]
static void Main(string[] args)
{
//Image bmp;
//bmp = Image.FromFile("teste.jpg");
//PaintEventArgs e;
//teste2.Quantize(bmp);
Application.Run(new Quantization());
/*
System.Console.WriteLine("Hello, World!");
System.Console.ReadLine();*/
}
}
The class:
namespace ImageManipulation
{
public unsafe abstract class Quantizer
{
/// <summary>
/// Construct the quantizer
/// </summary>
/// <param name="singlePass">If true, the quantization only needs to loop through the source pixels once</param>
/// <remarks>
/// If you construct this class with a true value for singlePass, then the code will, when quantizing your image,
/// only call the 'QuantizeImage' function. If two passes are required, the code will call 'InitialQuantizeImage'
/// and then 'QuantizeImage'.
/// </remarks>
public Quantizer(bool singlePass)
{
_singlePass = singlePass;
}
/// <summary>
/// Quantize an image and return the resulting output bitmap
/// </summary>
/// <param name="source">The image to quantize</param>
/// <returns>A quantized version of the image</returns>
public Bitmap Quantize()//Image source)
{
Image source = Image.FromFile("C:\Users\crashboy\Downloads\image009.jpg");
// Get the size of the source image
int height = source.Height;
int width = source.Width;
// And construct a rectangle from these dimensions
Rectangle bounds = new Rectangle(0, 0, width, height);
// First off take a 32bpp copy of the image
Bitmap copy = new Bitmap(width, height, PixelFormat.Format32bppArgb);
// And construct an 8bpp version
Bitmap output = new Bitmap(width, height, PixelFormat.Format8bppIndexed);
// Now lock the bitmap into memory
using (Graphics g = Graphics.FromImage(copy))
{
g.PageUnit = GraphicsUnit.Pixel;
// Draw the source image onto the copy bitmap,
// which will effect a widening as appropriate.
g.DrawImage(source, bounds);
}
// Define a pointer to the bitmap data
BitmapData sourceData = null;
try
{
// Get the source image bits and lock into memory
sourceData = copy.LockBits(bounds, ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
// Call the FirstPass function if not a single pass algorithm.
// For something like an octree quantizer, this will run through
// all image pixels, build a data structure, and create a palette.
if (!_singlePass)
FirstPass(sourceData, width, height);
// Then set the color palette on the output bitmap. I'm passing in the current palette
// as there's no way to construct a new, empty palette.
output.Palette = this.GetPalette(output.Palette);
// Then call the second pass which actually does the conversion
SecondPass(sourceData, output, width, height, bounds);
}
finally
{
// Ensure that the bits are unlocked
copy.UnlockBits(sourceData);
}
// Last but not least, return the output bitmap
return output;
}
/// <summary>
/// Execute the first pass through the pixels in the image
/// </summary>
/// <param name="sourceData">The source data</param>
/// <param name="width">The width in pixels of the image</param>
/// <param name="height">The height in pixels of the image</param>
protected virtual void FirstPass(BitmapData sourceData, int width, int height)
{
// Define the source data pointers. The source row is a byte to
// keep addition of the stride value easier (as this is in bytes)
byte* pSourceRow = (byte*)sourceData.Scan0.ToPointer();
Int32* pSourcePixel;
// Loop through each row
for (int row = 0; row < height; row++)
{
// Set the source pixel to the first pixel in this row
pSourcePixel = (Int32*)pSourceRow;
// And loop through each column
for (int col = 0; col < width; col++, pSourcePixel++)
// Now I have the pixel, call the FirstPassQuantize function...
InitialQuantizePixel((Color32*)pSourcePixel);
// Add the stride to the source row
pSourceRow += sourceData.Stride;
}
}
/// <summary>
/// Execute a second pass through the bitmap
/// </summary>
/// <param name="sourceData">The source bitmap, locked into memory</param>
/// <param name="output">The output bitmap</param>
/// <param name="width">The width in pixels of the image</param>
/// <param name="height">The height in pixels of the image</param>
/// <param name="bounds">The bounding rectangle</param>
protected virtual void SecondPass(BitmapData sourceData, Bitmap output, int width, int height, Rectangle bounds)
{
BitmapData outputData = null;
try
{
// Lock the output bitmap into memory
outputData = output.LockBits(bounds, ImageLockMode.WriteOnly, PixelFormat.Format8bppIndexed);
// Define the source data pointers. The source row is a byte to
// keep addition of the stride value easier (as this is in bytes)
byte* pSourceRow = (byte*)sourceData.Scan0.ToPointer();
Int32* pSourcePixel = (Int32*)pSourceRow;
Int32* pPreviousPixel = pSourcePixel;
// Now define the destination data pointers
byte* pDestinationRow = (byte*)outputData.Scan0.ToPointer();
byte* pDestinationPixel = pDestinationRow;
// And convert the first pixel, so that I have values going into the loop
byte pixelValue = QuantizePixel((Color32*)pSourcePixel);
// Assign the value of the first pixel
*pDestinationPixel = pixelValue;
// Loop through each row
for (int row = 0; row < height; row++)
{
// Set the source pixel to the first pixel in this row
pSourcePixel = (Int32*)pSourceRow;
// And set the destination pixel pointer to the first pixel in the row
pDestinationPixel = pDestinationRow;
// Loop through each pixel on this scan line
for (int col = 0; col < width; col++, pSourcePixel++, pDestinationPixel++)
{
// Check if this is the same as the last pixel. If so use that value
// rather than calculating it again. This is an inexpensive optimisation.
if (*pPreviousPixel != *pSourcePixel)
{
// Quantize the pixel
pixelValue = QuantizePixel((Color32*)pSourcePixel);
// And setup the previous pointer
pPreviousPixel = pSourcePixel;
}
// And set the pixel in the output
*pDestinationPixel = pixelValue;
}
// Add the stride to the source row
pSourceRow += sourceData.Stride;
// And to the destination row
pDestinationRow += outputData.Stride;
}
}
finally
{
// Ensure that I unlock the output bits
output.UnlockBits(outputData);
}
}
/// <summary>
/// Override this to process the pixel in the first pass of the algorithm
/// </summary>
/// <param name="pixel">The pixel to quantize</param>
/// <remarks>
/// This function need only be overridden if your quantize algorithm needs two passes,
/// such as an Octree quantizer.
/// </remarks>
protected virtual void InitialQuantizePixel(Color32* pixel)
{
}
/// <summary>
/// Override this to process the pixel in the second pass of the algorithm
/// </summary>
/// <param name="pixel">The pixel to quantize</param>
/// <returns>The quantized value</returns>
protected abstract byte QuantizePixel(Color32* pixel);
/// <summary>
/// Retrieve the palette for the quantized image
/// </summary>
/// <param name="original">Any old palette, this is overrwritten</param>
/// <returns>The new color palette</returns>
protected abstract ColorPalette GetPalette(ColorPalette original);
/// <summary>
/// Flag used to indicate whether a single pass or two
