2018-8-10-WPF-修改图片颜色

2018-8-10-WPF-修改图片颜色

本文告诉大家如何修改图片的颜色，如去掉图片的蓝色

在 WPF 可以使用很多图片处理的方法，本文告诉大家的是一个图片处理，可以把处理的图片保存在文件。

在阅读本文，我假设大家是熟悉 WPF 的，至少了解 C# ，也知道图片的格式。

在 WPF 可以使用 ARBG 数组表示图片，本文修改图片颜色的方法就是使用 ARBG 数组的方法修改，修改里面的元素的值。

如我需要去掉图片的蓝色，就可以通过修改 ARBG 数组的元素，设置所有蓝色为 0 ，去掉蓝色。

读取图片

首先找到一张好看的图片，放在解决方案

读取解决方案的图片

var stream = Application.GetResourceStream(new Uri("pack://application:,,,/1.jpg")).Stream;

如果找不到图片，就是没有设置图片生成是 Resource

解析文件

创建 WriteableBitmap 需要使用 ImageSource 所以需要先解析

// 其他忽略代码 var bitmapImage = new BitmapImage(); bitmapImage.BeginInit(); bitmapImage.StreamSource = stream; bitmapImage.EndInit();

使用 BitmapImage 解析文件

创建图片

在读取图片之后就可以创建图片

var writeableBitmap = new WriteableBitmap(bitmapImage);

转换图片格式

如果读取到的图片不是 BGRA 的格式，就需要转换图片格式

var formatConvertedBitmap = new FormatConvertedBitmap(); formatConvertedBitmap.BeginInit(); formatConvertedBitmap.Source = bitmapImage; formatConvertedBitmap.DestinationFormat = PixelFormats.Bgra32; formatConvertedBitmap.EndInit();

使用这个代码可以把格式转为​​PixelFormats.Bgra32​​，需要重新创建图片

var stream = Application.GetResourceStream(new Uri("pack://application:,,,/1.jpg")).Stream; var bitmapImage = new BitmapImage(); bitmapImage.BeginInit(); bitmapImage.StreamSource = stream; bitmapImage.EndInit(); var formatConvertedBitmap = new FormatConvertedBitmap(); formatConvertedBitmap.BeginInit(); formatConvertedBitmap.Source = bitmapImage; formatConvertedBitmap.DestinationFormat = PixelFormats.Bgra32; formatConvertedBitmap.EndInit(); var writeableBitmap = new WriteableBitmap(formatConvertedBitmap);

尝试显示图片，可以看到图片还是很好看

读取数组

在图片可以看到图片是使用 BGRA 的格式数组，所以只需要读取图片数组就可以修改图片

在修改图片之前需要使用 Lock 函数，读取图片的数组长度可以使用这个代码

var length = writeableBitmap.PixelWidth * writeableBitmap.PixelHeight * writeableBitmap.Format.BitsPerPixel / 8;

这里知道使用的是 BGRA 也就是一个像素使用 4 个 byte ，一个图片的像素就是​​writeableBitmap.PixelWidth * writeableBitmap.PixelHeight​​​ 。这里 ​​writeableBitmap.Format.BitsPerPixel​​ 就是拿到一个像素的 bit 数。

转换数组

var backBuffer = (byte*) writeableBitmap.BackBuffer;

读取颜色就是从数组拿到值

for (int i = 0; i + 4 < length; i = i + 4) { var blue = backBuffer[i]; var green = backBuffer[i + 1]; var red = backBuffer[i + 2]; var alpha = backBuffer[i + 3]; }

修改颜色就是修改对应的值然后设置数组，如设置蓝色是 0 去掉蓝色

for (int i = 0; i + 4 < length; i = i + 4) { var blue = backBuffer[i]; var green = backBuffer[i + 1]; var red = backBuffer[i + 2]; var alpha = backBuffer[i + 3]; blue = 0; backBuffer[i] = blue; backBuffer[i + 1] = green; backBuffer[i + 2] = red; backBuffer[i + 3] = alpha; }

设置之后需要设置图片显示

writeableBitmap.AddDirtyRect(new Int32Rect(0, 0, writeableBitmap.PixelWidth, writeableBitmap.PixelHeight)); writeableBitmap.Unlock();

所以去掉图片的蓝色可以使用 RemoveBlue 函数，设置蓝色为 0 的方法就是读取蓝色然后修改数组

private unsafe void RemoveBlue(WriteableBitmap writeableBitmap) { writeableBitmap.Lock(); var length = writeableBitmap.PixelWidth * writeableBitmap.PixelHeight * writeableBitmap.Format.BitsPerPixel / 8; var backBuffer = (byte*) writeableBitmap.BackBuffer; for (int i = 0; i + 4 < length; i = i + 4) { var blue = backBuffer[i]; var green = backBuffer[i + 1]; var red = backBuffer[i + 2]; var alpha = backBuffer[i + 3]; blue = 0; backBuffer[i] = blue; backBuffer[i + 1] = green; backBuffer[i + 2] = red; backBuffer[i + 3] = alpha; } writeableBitmap.AddDirtyRect(new Int32Rect(0, 0, writeableBitmap.PixelWidth, writeableBitmap.PixelHeight)); writeableBitmap.Unlock(); }

去掉蓝色的图片

代码：​​WPF 修改图片颜色 1.2-CSDN下载​​

现在的程序看起来还不能使用，尝试添加几个依赖属性，用来修改图片的颜色

​​WPF 修改图片​​

首先在 xaml 添加几个控件

蓝色 绿色 红色 透明度

注意在页面设置数据

DataContext="{Binding RelativeSource={RelativeSource Self}}"

然后打开 cs 添加代码

private WriteableBitmap _writeableBitmap; public MainWindow() { InitializeComponent(); Image.Margin = new Thickness(10, 10, 10, 10); var stream = Application.GetResourceStream(new Uri("pack://application:,,,/1.jpg")).Stream; ChangeImage(stream); DataContext = this; } public static readonly DependencyProperty BlueProperty = DependencyProperty.Register( "Blue", typeof(double), typeof(MainWindow), new PropertyMetadata(default(double), (s, e) => ((MainWindow) s).ChangeArray())); public double Blue { get { return (double) GetValue(BlueProperty); } set { SetValue(BlueProperty, value); } } public static readonly DependencyProperty GreenProperty = DependencyProperty.Register( "Green", typeof(double), typeof(MainWindow), new PropertyMetadata(default(double), (s, e) => ((MainWindow) s).ChangeArray())); public double Green { get { return (double) GetValue(GreenProperty); } set { SetValue(GreenProperty, value); } } public static readonly DependencyProperty RedProperty = DependencyProperty.Register( "Red", typeof(double), typeof(MainWindow), new PropertyMetadata(default(double), (s, e) => ((MainWindow) s).ChangeArray())); public double Red { get { return (double) GetValue(RedProperty); } set { SetValue(RedProperty, value); } } public static readonly DependencyProperty AlphaProperty = DependencyProperty.Register( "Alpha", typeof(double), typeof(MainWindow), new PropertyMetadata(default(double), (s, e) => ((MainWindow) s).ChangeArray())); public double Alpha { get { return (double) GetValue(AlphaProperty); } set { SetValue(AlphaProperty, value); } } private void ChangeImage(Stream stream) { var bitmapImage = new BitmapImage(); bitmapImage.BeginInit(); bitmapImage.StreamSource = stream; bitmapImage.EndInit(); var formatConvertedBitmap = new FormatConvertedBitmap(); formatConvertedBitmap.BeginInit(); formatConvertedBitmap.Source = bitmapImage; formatConvertedBitmap.DestinationFormat = PixelFormats.Bgra32; formatConvertedBitmap.EndInit(); _writeableBitmap = new WriteableBitmap(formatConvertedBitmap); ChangeArray(); } private unsafe void ChangeArray() { var writeableBitmap = _writeableBitmap; if (writeableBitmap == null) { return; } writeableBitmap.Lock(); var length = writeableBitmap.PixelWidth * writeableBitmap.PixelHeight * writeableBitmap.Format.BitsPerPixel / 8; var backBuffer = (byte*) writeableBitmap.BackBuffer; var byteList = new byte[length]; for (int i = 0; i + 4 < length; i = i + 4) { var blue = backBuffer[i]; var green = backBuffer[i + 1]; var red = backBuffer[i + 2]; var alpha = backBuffer[i + 3]; blue += (byte) Blue; green += (byte) Green; red += (byte) Red; alpha += (byte) Alpha; byteList[i] = blue; byteList[i + 1] = green; byteList[i + 2] = red; byteList[i + 3] = alpha; } writeableBitmap.Unlock(); writeableBitmap = new WriteableBitmap(writeableBitmap.PixelWidth, writeableBitmap.PixelHeight, 96, 96, writeableBitmap.Format, writeableBitmap.Palette); writeableBitmap.Lock(); writeableBitmap.WritePixels(new Int32Rect(0, 0, writeableBitmap.PixelWidth, writeableBitmap.PixelHeight), byteList, writeableBitmap.BackBufferStride, 0); writeableBitmap.AddDirtyRect(new Int32Rect(0, 0, writeableBitmap.PixelWidth, writeableBitmap.PixelHeight)); writeableBitmap.Unlock(); Image.Source = writeableBitmap; } private void Button_OnClick(object sender, RoutedEventArgs e) { var openFileDialog = new OpenFileDialog(); openFileDialog.Filter = "jpg(*.jpg)|*.jpg"; if (openFileDialog.ShowDialog() == true) { var stream = openFileDialog.OpenFile(); ChangeImage(stream); } } public class DoubleConvert : IValueConverter { /// public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { if (value is double n) { return n.ToString("0.00"); } return DependencyProperty.UnsetValue; } /// public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { return null; } }

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