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2009/04/28(Tue) 16:31:52 編集(投稿者)
2009/04/28(Tue) 16:31:47 編集(投稿者)
余計な処理は除いてますが、以下コードです。現象は再現します。
using System;
using System.IO;
using System.Drawing;
using System.Windows.Forms;
using System.Drawing.Imaging;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
int x = 0;
int y = 0;
int posx = 0;
int posy = 0;
Bitmap bmp;
public Form1()
{
InitializeComponent();
this.pictureBox1.MouseMove += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseMove);
this.pictureBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseDown);
this.pictureBox1.Paint += new System.Windows.Forms.PaintEventHandler(this.pictureBox1_Paint);
bmp = (Bitmap)Image.FromStream(File.OpenRead(@"c:\test.jpg"), false, false); //←①の読込処理です。
ConvFile(); //←②の画像処理です。ここをコメント化するかしないかで描画速度が変わります。
}
public void ConvFile()
{
BitmapData d = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
int residual = d.Stride - d.Width * 3;
unsafe
{
byte* p = (byte*)(void*)d.Scan0;
for (int y = 0; y < d.Height; ++y)
{
for (int x = 0; x < d.Width; ++x)
{
p[2] += 0; //実際は計算値を代入しています
p[1] += 0;
p[0] += 0;
p += 3;
}
p += residual;
}
}
bmp.UnlockBits(d);
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawImage(bmp, x, y, bmp.Width, bmp.Height);
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
posx = e.X;
posy = e.Y;
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button != MouseButtons.Left) return;
x -= posx - e.X;
y -= posy - e.Y;
pictureBox1.Invalidate();
posx = e.X;
posy = e.Y;
}
}
}
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