Question

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

namespace ConvertBitmapToArray
{
    public partial class Form1 : Form
    {

        public Form1()
        {
            InitializeComponent();

            Bitmap bitmap = new Bitmap(@"C:\Temp\Gimp Maps\Bitmaps\test1.bmp");
            CreateArray(bitmap);

            File.Create(@"C:\Temp\Gimp Maps\Maps.cs");
        }

        private void CreateArray(Bitmap bmp)
        {
            Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
            System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, bmp.PixelFormat);

            IntPtr ptr = bmpData.Scan0;
            int bytes = Math.Abs(bmpData.Stride) * bmp.Height;
            byte[] rgbValues = new byte[bytes];
            System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
            System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);

            bmp.UnlockBits(bmpData);

            for (int i = 0; i < rgbValues.Count(); i++)
            {

            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

我有一个黑白尺寸8x8或800x800的位图，我得到了rgbValues数组。现在循环：

for (int i = 0; i < rgbValues.Count(); i++)
{

}

我想创建从0和1构建的2d int数组。例如：

int[,] map = new int[,] 
{
    {0,0,0,0,0,0,0,0,},
    {0,0,0,0,0,0,0,0,},
    {0,0,0,0,0,0,0,0,},
    {1,1,1,1,0,0,0,0,},
    {0,0,0,1,0,0,0,0,},
    {0,0,1,1,0,0,0,0,},
    {0,0,0,0,1,1,1,0,},
    {0,0,0,0,0,0,0,1,},
};

因此255将为0而0将为1.在int数组示例中，1为黑色，0为白色。

我试过了：

private void CreateArray(Bitmap bmp)
{
    int[] pix = new int[bmp.Width*bmp.Height];

    int x, y, rgb, val;
    for (y = 0; y < bmp.Height; y++)
    {
        for (x = 0; x < bmp.Width; x++)
        {
            Color c = bmp.GetPixel(x, y);
            rgb = c.ToArgb();
            if (rgb == 0xff000000) // if black
            { 
                val = 0;
            }
            else
                val = 1;
            pix[y * bmp.Width + x] = val;
        }
    }
}

但是我不确定Color c和rgb = c.ToArgb（）;

在if条件下，我得到绿线说：

警告1 与积分常数的比较是没用的;常量超出了'int'类型的范围

如何使用LockBits或GetPixel执行此操作？我想知道使用每种方法有多么不同。

这就是我到目前为止所做的：

private void CreateArray(Bitmap bmp)
        {
            int[,] array = new int[,]
            {

            };

            // Lock the bitmap's bits.  
            Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
            System.Drawing.Imaging.BitmapData bmpData =
                bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
                bmp.PixelFormat);

            // Get the address of the first line.
            IntPtr ptr = bmpData.Scan0;

            // Declare an array to hold the bytes of the bitmap. 
            int bytes  = Math.Abs(bmpData.Stride) * bmp.Height;
            byte[] rgbValues = new byte[bytes];


            int x, y, rgb, val;
            for (y = 0; y < bmp.Height; y++)
            {
                for (x = 0; x < bmp.Width; x++)
                {
                    var row = ptr + (y * bmpData.Stride);
                    var pixel = row + x * ; // bpp will be 4 in your case

                    // A bit=0
                    // R bit=1
                    // G bit=2
                    // B bit=3
                    // (depending on your image pixel format)
                    for (var bit = 0; bit < bpp; bit++)
                    {
                        var pixelComponent = pixel[bit];
                    }
                }
            }
        }

Answer 1

要以更合理的方式遍历图像的字节，请将unsafe关键字添加到函数签名（private unsafe void ...），并确保通过项目属性启用unsafe代码

var pt = (byte*)bmpData.Scan0;

现在您可以轻松遍历x和y：

var row = pt + (y * bmpData.Stride);
var pixel = row + x * bpp; // bpp will be 4 in your case

// A bit=0
// R bit=1
// G bit=2
// B bit=3
// (depending on your image pixel format)
for (var bit = 0; bit < bpp; bit++)
{
    var pixelComponent = pixel[bit];
}

如果您确实希望最终结果为二维数组，则应使用[,]或[][]代替[]（单维数组）

LockBits方法与GetPixel方法之间的巨大差异是性能。 GetPixel实际上锁定了这些位，检索了一个像素并再次解锁了这些位 - 这意味着在多次重复执行时会出现可怕的性能。

修改

以下是完整的代码：

private unsafe void CreateArray(Bitmap bmp) { // Note that is it somewhat a standard // to define 2d array access by [y,x] (not [x,y]) bool[,] bwValues = new bool[bmp.Height, bmp.Width]; // Lock the bitmap's bits. Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height); System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, bmp.PixelFormat); // Get the address of the first line. byte* ptr = (byte*)bmpData.Scan0; // Declare an array to hold the bytes of the bitmap. int bytes = Math.Abs(bmpData.Stride) * bmp.Height; for (int y = 0; y < bmp.Height; y++) { var row = ptr + (y * bmpData.Stride); for (int x = 0; x < bmp.Width; x++) { var pixel = row + x * 4; // ARGB has 4 bytes per pixel // A bit=0 // R bit=1 // G bit=2 // B bit=3 // (depending on your image pixel format) // Check if A = R = G = B = 255 (meaning the pixel is white) bool isWhite = (pixel[0] == 255 && pixel[1] == 255 && pixel[2] == 255 && pixel[3] == 255); // Assume that anything that isn't white is black bwValues[y, x] = isWhite; } } // Do whatever you want with vwValues here }

如何将rgbvalues 0和255的位图数组转换为0和1的2d int数组？

1 个答案: