请想象我有一个非常简单的棋盘图像。
这里我用字母表示像素的图像：黑色像素“B”，白色像素“W”
这是起始的2x2像素图像：
BW
WB
我想调整图像大小，让我说2x的比例给我：
BBWW
BBWW
WWBB
WWBB
或缩放4x
BBBBWWWW
BBBBWWWW
WWWWBBBB
WWWWBBBB
因此像素颜色不会以任何方式抖动。
我在C＃中尝试了这个但是图像很乱，所有都抖动了，我需要学习如何在没有抖动/颜色变化的情况下做到这一点。
到目前为止，这是我的代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Text;
namespace PageTwine
{
public partial class RandonGiff : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
// create 2x2 chequerboard:
Bitmap oBitmap = new Bitmap(2, 2);
Graphics oGraphic = Graphics.FromImage(oBitmap);
// color black pixels (i think the default is black but this helps to explain)
SolidBrush oBrush = new SolidBrush(Color.FromArgb(255, 255, 255));
oGraphic.FillRectangle(oBrush, 0, 0, 1, 1);
oGraphic.FillRectangle(oBrush, 1, 1, 1, 1);
//color white pixels
oBrush = new SolidBrush(Color.FromArgb(0, 0, 0));
oGraphic.FillRectangle(oBrush, 0, 1, 1, 1);
oGraphic.FillRectangle(oBrush, 1, 0, 1, 1);
// expand to 4x4
Bitmap result = new Bitmap(4, 4);
using (Graphics graphics = Graphics.FromImage(result))
{
// I don't know what these settings should be :
graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.None;
//draw the image into the target bitmap
graphics.DrawImage(oBitmap, 0, 0, result.Width, result.Height);
}
//send image directly to the browser
Response.ContentType = "image/gif";
result.Save(Response.OutputStream, ImageFormat.Gif);
}
}
}
结果是抖动的图像，但我需要干净清脆的棋盘效果。 请你帮帮我。
感谢您提出的建议，但我仍然在寻找解决方案。
我创建了一个演示页面，您可以自己查看结果。
演示的URL是：
http://www.leansoftware.net/servicedesk/publicadhoc/randomgif.aspx?columns=3&rows=3
演示将创建一个chequerboard，初始列x行作为像素，然后放大到gif图像300x300 px。
你会看到颜色扭曲/有点 - 我想解决这个问题。
以下是演示的源代码：
using System;
using System.Collections.Generic;
using System.Web;
using System.IO;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Text;
using System.Linq;
public partial class RandomGif : System.Web.UI.Page
{
public class Coordinates
{
public int x { get; set; }
public int y { get; set; }
}
static Random rand = new Random();
protected void Page_Load(object sender, EventArgs e)
{
// Output type gif
int iwidth;
int iheight;
int bits;
Response.ContentType = "image/gif";
// Get parameters
if (Request.QueryString["count"] != null)
{
bits = Convert.ToInt32(Request.QueryString["count"]);
int square = Convert.ToInt32(Math.Ceiling(Math.Sqrt(bits + Math.Floor(bits / 4.0))));
iwidth = square;
iheight = square;
bits = (square * square)-1;
}
else
if (Request.QueryString["rows"] != null && Request.QueryString["columns"] != null)
{
iwidth = Convert.ToInt32(Request.QueryString["columns"]);
iheight = Convert.ToInt32(Request.QueryString["rows"]);
bits = (iwidth * iheight);
}
else {
return;
}
if (bits > 1000){
Response.Write("Please specify a grid <= 1000 pixels");
return;
}
int plotCount = 0;
//web safe colors : 00, 33, 66, 99, CC, FF;
List<int> webSafeColor = new List<int>();
webSafeColor.Add(0); //00
webSafeColor.Add(51);//33
webSafeColor.Add(102);//66
webSafeColor.Add(153);//99
webSafeColor.Add(204);//CC
webSafeColor.Add(255);//FF
// Create a structure to hold all possible coordinates
var Grid = new List<Coordinates>();
for (int xi = 1; xi <= iwidth; xi++)
{
for (int yi = 1; yi <= iheight; yi++)
{
Grid.Add(new Coordinates { x = xi, y = yi });
plotCount++;
}
}
//create a new Bitmap object
Bitmap oBitmap = new Bitmap(iwidth, iheight);
//create a new Graphics object, which will allow us to draw on our bitmap:
Graphics oGraphic = Graphics.FromImage(oBitmap);
//fill the image rectangle with n bits
for (int i = 1; i <= bits; i++)
{
//Random rand = new Random();
int row = rand.Next(Grid.Count());
// random red
int ircolor = webSafeColor[rand.Next(5)];
// random green
int igcolor = webSafeColor[rand.Next(5)];
// random blue
int ibcolor = webSafeColor[rand.Next(5)];
Color randomColor = Color.FromArgb(ircolor, igcolor, ibcolor);
SolidBrush oBrush = new SolidBrush(randomColor);
oGraphic.FillRectangle(oBrush, Grid[row].x - 1, Grid[row].y - 1, 1, 1);
// Delete this coordinate#
Grid.Remove(Grid[row]);
}
// resize image
Bitmap result = new Bitmap(300, 300);
using (Graphics graphics = Graphics.FromImage(result))
{
//set the resize quality modes to high quality
graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.AssumeLinear;
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
//draw the image into the target bitmap
graphics.DrawImage(oBitmap, 0, 0, result.Width, result.Height);
}
//send image directly to the browser
Response.ContentType = "image/gif";
result.Save(Response.OutputStream, ImageFormat.Gif);
}
}
如果您可以建议修改，我们可以尝试一下，看看它是否解决了问题。
谢谢理查德
答案 0 :(得分：2)
这可能是c# Draw Image (Scaled) to Graphics, does not interpolate correctly. Fixes?
的副本您需要添加：
graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
或者，您可以使用
graphics.DrawImage(oBitmap, 0, 0, result.Width * 2, result.Height * 2);
实现类似的强制画笔填充而不会在右下角图像边缘处扭曲的效果。
更新：
添加使用自定义调色板创建索引图像的链接。 http://support.microsoft.com/kb/319061
答案 1 :(得分：0)
使用：
System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;