如何用纯色填充位图？

Question

I need to create a 24-bit bitmap (resolution 100x100 pixels) using a unique RGB color and save the generated image to the disk. I currently use the SetPixel function, but it is extremely slow.

Bitmap Bmp = new Bitmap(width, height);
//...
//...
Bmp.SetPixel(x,y,Color.FromARGB(redvalue, greenvalue, bluevalue));

Is there a faster method than SetPixel ? Thanks in advance.

Answer 1

This should do what you need it to. It will fill the entire bitmap with the specified color.

Bitmap Bmp = new Bitmap(width, height);
using (Graphics gfx = Graphics.FromImage(Bmp))
using (SolidBrush brush = new SolidBrush(Color.FromArgb(redvalue, greenvalue, bluevalue)))
{
    gfx.FillRectangle(brush, 0, 0, width, height);
}

Answer 2

Bitmap bmp = new Bitmap(width, height);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.Green);

Answer 3

It depends on what you are trying to accomplish, but usually you would use GDI+ by getting a graphics object and then drawing to it:

Graphics g = Graphics.FromImage(bitmap); 

Its actually a big subject, here are some beginner tutorials: GDI+ Tutorials

Here is a snippet from the tutorial on drawing a rectangle with a gradient fill.

Rectangle rect = new Rectangle(50, 30, 100, 100); 
LinearGradientBrush lBrush = new LinearGradientBrush(rect, Color.Red, Color.Yellow, LinearGradientMode.BackwardDiagonal); 
g.FillRectangle(lBrush, rect); 

Answer 4

您可以使用LockBits来加速写入像素（指针访问而不是每个像素的方法调用）。

Answer 5

始终使用区域（矩形）比使用单个像素快得多。

Answer 6

You're spoilt for choice here :-)

An alternative to using GDI+ is to use WPF (see RenderTargetBitmap.Render .)

Also see this question .

Answer 7

Creating bitmap object bmp of Size s (height , width) and Color c.

bmp = CreateBmp(c, s);

Now CreateBmp method which returns bitmap:

Bitmap CreateBmp(Color c, Size s)
{
    Bitmap temp =new Bitmap(1, 1);
    temp.SetPixel(0, 0, c);
    return new Bitmap(temp, s);
}

Answer 8

I suggest checking out the GD Library.

I'm rather certain there is ac# library. http://www.boutell.com/gd/

Answer 9

是或不是：透明是一种颜色