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WPF 修改圖片顏色

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原文:WPF 修改圖片顏色

本文告訴大家如何修改圖片的顏色,如去掉圖片的藍色

在 WPF 可以使用很多圖片處理的方法,本文告訴大家的是一個圖片處理,可以把處理的圖片保存在文件。

在閱讀本文,我假設大家是熟悉 WPF 的,至少了解 C# ,也知道圖片的格式。

在 WPF 可以使用 ARBG 數組表示圖片,本文修改圖片顏色的方法就是使用 ARBG 數組的方法修改,修改裏面的元素的值。

如我需要去掉圖片的藍色,就可以通過修改 ARBG 數組的元素,設置所有藍色為 0 ,去掉藍色。

讀取圖片

首先找到一張好看的圖片,放在解決方案

技術分享圖片

讀取解決方案的圖片

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

如果找不到圖片,就是沒有設置圖片生成是 Resource

解析文件

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

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

使用 BitmapImage 解析文件

創建圖片

在讀取圖片之後就可以創建圖片

            var writeableBitmap = new WriteableBitmap(bitmapImage);

轉換圖片格式

如果讀取到的圖片不是 BGRA 的格式,就需要轉換圖片格式

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

使用這個代碼可以把格式轉為PixelFormats.Bgra32,需要重新創建圖片

            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);

嘗試顯示圖片,可以看到圖片還是很好看

技術分享圖片

讀取數組

在圖片可以看到圖片是使用 BGRA 的格式數組,所以只需要讀取圖片數組就可以修改圖片

讀取圖片需要使用不安全代碼,需要右擊項目屬性,點擊生成,允許不安全代碼。

在修改圖片之前需要使用 Lock 函數,讀取圖片的數組長度可以使用這個代碼

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

這裏知道使用的是 BGRA 也就是一個像素使用 4 個 byte ,一個圖片的像素就是writeableBitmap.PixelWidth * writeableBitmap.PixelHeight 。這裏 writeableBitmap.Format.BitsPerPixel 就是拿到一個像素的 bit 數。

轉換數組

            var backBuffer = (byte*) writeableBitmap.BackBuffer;

讀取顏色就是從數組拿到值

            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];
            }

修改顏色就是修改對應的值然後設置數組,如設置藍色是 0 去掉藍色

            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;
            }

設置之後需要設置圖片顯示


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

所以去掉圖片的藍色可以使用 RemoveBlue 函數,設置藍色為 0 的方法就是讀取藍色然後修改數組

        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();
        }

去掉藍色的圖片

技術分享圖片

代碼:WPF 修改圖片顏色 1.2-CSDN下載

現在的程序看起來還不能使用,嘗試添加幾個依賴屬性,用來修改圖片的顏色

技術分享圖片

可以點擊這裏下載程序

WPF 修改圖片

首先在 xaml 添加幾個控件

    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="485*" />
            <ColumnDefinition Width="308*" />
        </Grid.ColumnDefinitions>
        <Image x:Name="Image" />
        <Grid Grid.Column="1">
            <Grid VerticalAlignment="Center">
                <FrameworkElement.Resources>
                    <Style TargetType="Slider">
                        <Setter Property="Width" Value="100" />
                        <Setter Property="HorizontalAlignment" Value="Center" />
                        <Setter Property="Margin" Value="10,10,10,10" />
                        <Setter Property="Minimum" Value="-255" />
                        <Setter Property="Maximum" Value="255" />
                    </Style>

                    <Style TargetType="TextBlock">
                        <Setter Property="Margin" Value="10,10,10,10" />
                        <Setter Property="HorizontalAlignment" Value="Center" />
                    </Style>

                    <local:DoubleConvert x:Key="DoubleConvert" />
                </FrameworkElement.Resources>

                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <TextBlock>藍色</TextBlock>
                <TextBlock Grid.Row="1" Grid.Column="0">綠色</TextBlock>
                <TextBlock Grid.Row="2" Grid.Column="0">紅色</TextBlock>
                <TextBlock Grid.Row="3" Grid.Column="0">透明度</TextBlock>

                <!-- 藍色 -->
                <Slider Grid.Row="0" Grid.Column="1" Value="{Binding Path=Blue,Mode=TwoWay}" />
                <!-- 綠色 -->
                <Slider Grid.Row="1" Grid.Column="1" Value="{Binding Path=Green,Mode=TwoWay}" />
                <!-- 紅色 -->
                <Slider Grid.Row="2" Grid.Column="1" Value="{Binding Path=Red,Mode=TwoWay}" />
                <!-- 透明度 -->
                <Slider Grid.Row="3" Grid.Column="1" Value="{Binding Path=Alpha,Mode=TwoWay}" />

                <!-- 藍色 -->
                <TextBlock Grid.Row="0" Grid.Column="2"
                           Text="{Binding Path=Blue,Mode=OneWay,Converter={StaticResource DoubleConvert}}" />
                <!-- 綠色 -->
                <TextBlock Grid.Row="1" Grid.Column="2"
                           Text="{Binding Path=Green,Mode=OneWay,Converter={StaticResource DoubleConvert}}" />
                <!-- 紅色 -->
                <TextBlock Grid.Row="2" Grid.Column="2"
                           Text="{Binding Path=Red,Mode=OneWay,Converter={StaticResource DoubleConvert}}" />
                <!-- 透明度 -->
                <TextBlock Grid.Row="3" Grid.Column="2"
                           Text="{Binding Path=Alpha,Mode=OneWay,Converter={StaticResource DoubleConvert}}" />
            </Grid>
            <Grid VerticalAlignment="Bottom">
                <Button Margin="10,10,10,10" Content="替換圖片" Click="Button_OnClick" />
            </Grid>
        </Grid>
    </Grid>

註意在頁面設置數據

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

然後打開 cs 添加代碼

      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
    {
        /// <inheritdoc />
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value is double n)
            {
                return n.ToString("0.00");
            }

            return DependencyProperty.UnsetValue;
        }

        /// <inheritdoc />
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return null;
        }
    }

代碼:WPF 修改圖片顏色 2.5-CSDN下載

參見:

How to: Convert a BitmapSource to a Different PixelFormat


本文會經常更新,請閱讀原文: https://lindexi.gitee.io/lindexi/post/WPF-%E4%BF%AE%E6%94%B9%E5%9B%BE%E7%89%87%E9%A2%9C%E8%89%B2.html ,以避免陳舊錯誤知識的誤導,同時有更好的閱讀體驗。

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WPF 修改圖片顏色