快速的方式来创建位图阵列的大的位图? [英] fast way to create a big bitmap from an array of bitmap?
问题描述
我有这样的code,
复制/粘贴在一个新的winform应用程序,如果你运行它这个会写你的桌面上的文件: test123abcd.png
copy/paste in a new winform app and this will write a file on your desktop if you run it: test123abcd.png
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Dim SquareSize = 5
Dim GridX = 2500
Dim GridY = 2500
Dim SquareCount = GridX * GridY - 1
Dim sw As New Stopwatch
Dim Rect(4) As Rectangle
Rect(0) = New Rectangle(0, 3, 3, 1)
Rect(1) = New Rectangle(3, 0, 1, 3)
Rect(2) = New Rectangle(3, 3, 3, 1)
Rect(3) = New Rectangle(0, 0, 1, 3)
Dim fullsw = Stopwatch.StartNew
Using board = New Bitmap(SquareSize * (GridX + 1), SquareSize * (GridY + 1), Imaging.PixelFormat.Format32bppPArgb)
Using graph = Graphics.FromImage(board)
Using _board = New Bitmap(SquareSize, SquareSize, Imaging.PixelFormat.Format32bppPArgb)
Using g As Graphics = Graphics.FromImage(_board)
For i = 0 To SquareCount
g.Clear(If((i And 1) = 1, Color.Red, Color.Blue))
g.FillRectangles(Brushes.White, Rect)
sw.Start()
graph.DrawImageUnscaled(_board, ((i Mod GridX) * SquareSize), ((i \ GridY) * SquareSize))
sw.Stop()
Next
End Using
End Using
End Using
fullsw.Stop()
board.Save(Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory) & "\test123abcd.png", Imaging.ImageFormat.Png)
End Using
MessageBox.Show("Full SW: " & fullsw.ElapsedMilliseconds & Environment.NewLine &
"DrawImageUnscaled SW: " & sw.ElapsedMilliseconds)
End Sub
中所花费的时间大约40%至45%是在 DrawImageUnscaled
,约23秒我目前的电脑上,而整个事情需要约50秒。
about 40% to 45% of the time spent is on DrawImageUnscaled
, about 23 seconds on my current computer while the whole thing take about 50 seconds
是有办法加快 DrawImageUnscaled
? (也许整个事情?)
is there a way to speed up DrawImageUnscaled
? (and maybe the whole thing?)
修改 - 在vb.net的问题,答案在C#
EDIT - question in vb.net, answer in c#
推荐答案
哇,我喜欢当它worthed不安全code,解决了我用C#问题到底
wow I like unsafe code when it is worthed, solved my problem with c# in the end
这里是code,这是我的问题。
here is the code, which is about 70x faster to the code in my question
using System;
using System.Drawing;
using System.Drawing.Imaging;
namespace BmpFile
{
public class BmpTest
{
private const int PixelSize = 4;
public static long Test(int GridX, int GridY, int SquareSize, Rectangle[][] Rect)
{
Bitmap bmp = new Bitmap(GridX * SquareSize, GridY * SquareSize, PixelFormat.Format32bppArgb);
BitmapData bmd = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height),
System.Drawing.Imaging.ImageLockMode.ReadWrite,
bmp.PixelFormat);
int Stride = bmd.Stride;
int Height = bmd.Height;
int Width = bmd.Width;
int RectFirst = Rect.GetUpperBound(0);
int RectSecond;
int Offset1, Offset2, Offset3;
int i, j, k, l, w, h;
int FullRow = SquareSize * Stride;
int FullSquare = SquareSize * PixelSize;
var sw = System.Diagnostics.Stopwatch.StartNew();
unsafe
{
byte* row = (byte*)bmd.Scan0;
//draw all rectangles
for (i = 0; i <= RectFirst; ++i)
{
Offset1 = ((i / GridX) * FullRow) + ((i % GridX) * FullSquare) + 3;
RectSecond = Rect[i].GetUpperBound(0);
for (j = 0; j <= RectSecond; ++j)
{
Offset2 = Rect[i][j].X * PixelSize + Rect[i][j].Y * Stride;
w=Rect[i][j].Width;
h=Rect[i][j].Height;
for (k = 0; k <= w; ++k)
{
Offset3 = k * PixelSize;
for (l = 0; l <= h; ++l)
{
row[Offset1 + Offset2 + Offset3 + (l * Stride)] = 255;
}
}
}
}
//invert color
for (int y = 0; y < Height; y++)
{
Offset1 = (y * Stride) + 3;
for (int x = 0; x < Width; x++)
{
if (row[Offset1 + x * PixelSize] == 255)
{
row[Offset1 + x * PixelSize] = 0;
}
else
{
row[Offset1 + x * PixelSize] = 255;
}
}
}
}
sw.Stop();
bmp.UnlockBits(bmd);
bmp.Save(Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + @"\test.png", ImageFormat.Png);
bmp.Dispose();
return sw.ElapsedMilliseconds;
}
}
}
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