C#

int w=1000;
int h=1000;
Bitmap bm=new Bitmap(w,h);
for (int y=0; y< h; y++) {
    for (int x=0; x< w; x++) {
        bm.SetPixel(x, y, someColor);
    }
}

Luc Pattyn [Forum Guidelines] [My Articles]

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Fixturized forever.

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Luc Pattyn wrote:

a little Google action

Luc Pattyn wrote:

so you are creating one million pens and wondering why it is sooo slow?

<br />
// (Some of these may not be necessary.)<br />
using System;<br />
using System.Collections.Generic;<br />
using System.ComponentModel;<br />
using System.Data;<br />
using System.Drawing;<br />
using System.Text;<br />
using System.Windows.Forms;<br />
using System.Runtime.InteropServices;<br />
using System.Drawing.Imaging;<br />
<br />
    // Could use enumeration here.<br />
    const int bmB = 0;<br />
    const int bmG = 1;<br />
    const int bmR = 2;<br />
    const int bmA = 3;<br />
   <br />
    //<br />
    // Allocate a pixel array to match the bitmap.<br />
    //<br />
    int bitsPerPixel;<br />
    bool hasAlpha;<br />
    switch (bitmap.PixelFormat)<br />
    {<br />
        case PixelFormat.Format24bppRgb:<br />
	    bitsPerPixel = 24;<br />
            hasAlpha = false;<br />
	    break;<br />
        case PixelFormat.Format32bppRgb:<br />
            bitsPerPixel = 32;<br />
            hasAlpha = false;<br />
        case PixelFormat.Format32bppArgb:<br />
        case PixelFormat.Format32bppPArgb:<br />
            bitsPerPixel = 32;<br />
            hasAlpha = true;<br />
            break;<br />
        default:<br />
            throw new ArgumentException("Unsupported pixel format.");<br />
    }<br />
<br />
    // (Stride is available in the BitmapData structure.)<br />
    int bytesPerPixel = bitsPerPixel >> 3;<br />
    int stride = ((bitmap.Width * bitsPerPixel + 31) & ~31) >> 3;<br />
    int bitmapBytes = stride * bitmap.Height;<br />
    byte[] pixels = new byte[bitmapBytes];<br />
<br />
...<br />
    //<br />
    // Copy the bitmap into the pixel array.<br />
    //<br />
<br />
    // Lock the bitmap's bits.<br />
    BitmapData bmpData = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadWrite, bitmap.PixelFormat);<br />
<br />
    // Copy the bitmap pixels into the array.<br />
    Marshal.Copy(bmpData.Scan0, pixels, 0, bitmapBytes);<br />
<br />
    // Unlock the bits.<br />
    bitmap.UnlockBits(bmpData);<br />
<br />
...<br />
    //<br />
    // Copy the pixel array into the bitmap.<br />
    //<br />
<br />
    // Lock the bitmap's bits.  <br />
    BitmapData bmpData = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadWrite, bitmap.PixelFormat);<br />
<br />
    // Copy the array back into the bitmap.<br />
    Marshal.Copy(pixels, 0, bmpData.Scan0, bitmapBytes);<br />
<br />
    // Unlock the bits.<br />
    bitmap.UnlockBits(bmpData);<br />
	<br />