C#、WPF、バイリニア法での画像の拡大縮小変換、24bitカラー対応とマルチスレッド対応版
昨日のグレースケール専用を改変して
カラーの対応ピクセルフォーマットはBgr24
マルチスレッド化は二重のForループの外側1つをParallel.Forにしただけ
コード
縮小変換専用
/// <summary> /// 画像の縮小、バイリニア法で補完、PixelFormats.Bgr24専用) /// </summary> /// <param name="source">PixelFormats.Bgr24のBitmap</param> /// <param name="yoko">変換後の横ピクセル数を指定</param> /// <param name="tate">変換後の縦ピクセル数を指定</param> /// <returns></returns> private BitmapSource BilinearBgr24縮小専用(BitmapSource source, int yoko, int tate) { //元画像の画素値の配列作成 int sourceWidth = source.PixelWidth; int sourceHeight = source.PixelHeight; int stride = (sourceWidth * source.Format.BitsPerPixel + 7) / 8; byte[] pixels = new byte[sourceHeight * stride]; source.CopyPixels(pixels, stride, 0); //変換後の画像の画素値の配列用 double yokoScale = (double)sourceWidth / yoko;//横倍率 double tateScale = (double)sourceHeight / tate; //1ピクセルあたりのバイト数、Byte / Pixel int pByte = (source.Format.BitsPerPixel + 7) / 8; int scaledStride = yoko * pByte; byte[] resultPixels = new byte[tate * scaledStride]; _ = Parallel.For(0, tate, y => { for (int x = 0; x < yoko; x++) { //参照範囲の左上座標bp double bpX = ((x + 0.5) * yokoScale) - 0.5; double bpY = ((y + 0.5) * tateScale) - 0.5; //小数部分s double sx = bpX % 1; double sy = bpY % 1; //面積 double d = sx * sy; double c = (1 - sx) * sy; double b = sx * (1 - sy); double a = 1 - (d + c + b);// (1 - sx) * (1 - sy) //左上ピクセルの座標は //参照範囲の左上座標の小数部分を切り捨て(整数部分) //左上ピクセルのIndex int i = ((int)bpY * stride) + ((int)bpX * pByte); //各区の値*面積の合計を四捨五入して完成 //Blue resultPixels[y * scaledStride + x * pByte] = (byte)(pixels[i] * a + pixels[i + pByte] * b + pixels[i + stride] * c + pixels[i + stride + pByte] * d + 0.5); //Green resultPixels[y * scaledStride + x * pByte + 1] = (byte)(pixels[i + 1] * a + pixels[i + pByte + 1] * b + pixels[i + stride + 1] * c + pixels[i + stride + pByte + 1] * d + 0.5); //Red resultPixels[y * scaledStride + x * pByte + 2] = (byte)(pixels[i + 2] * a + pixels[i + pByte + 2] * b + pixels[i + stride + 2] * c + pixels[i + stride + pByte + 2] * d + 0.5); } }); BitmapSource bitmap = BitmapSource.Create(yoko, tate, 96, 96, source.Format, null, resultPixels, scaledStride); return bitmap; }
拡大変換対応版
//縮小拡大対応版 /// <summary> /// 画像の拡大縮小、バイリニア法で補完(PixelFormats.Bgr24専用) /// </summary> /// <param name="source">PixelFormats.Bgr24のBitmap</param> /// <param name="yoko">横ピクセル数を指定</param> /// <param name="tate">縦ピクセル数を指定</param> /// <returns></returns> private BitmapSource BilinearBgr24専用(BitmapSource source, int yoko, int tate) { //元画像の画素値の配列作成 int sourceWidth = source.PixelWidth; int sourceHeight = source.PixelHeight; int stride = (sourceWidth * source.Format.BitsPerPixel + 7) / 8; byte[] pixels = new byte[sourceHeight * stride]; source.CopyPixels(pixels, stride, 0); //縮小後の画像の画素値の配列用 double yokoScale = (double)sourceWidth / yoko;//横倍率 double tateScale = (double)sourceHeight / tate; //1ピクセルあたりのバイト数、Byte / Pixel int pByte = (source.Format.BitsPerPixel + 7) / 8; int scaledStride = yoko * pByte; byte[] resultPixels = new byte[tate * scaledStride]; _ = Parallel.For(0, tate, y => { for (int x = 0; x < yoko; x++) { //参照範囲の左上座標bp double bpX = ((x + 0.5) * yokoScale) - 0.5; //画像範囲内チェック、参照範囲が画像から外れていたら修正(収める) if (bpX < 0) { bpX = 0; } if (bpX > sourceWidth - 1) { bpX = sourceWidth - 1; } double bpY = (y + 0.5) * tateScale - 0.5; if (bpY < 0) { bpY = 0; } if (bpY > sourceHeight - 1) { bpY = sourceHeight - 1; } //小数部分s double sx = bpX % 1; double sy = bpY % 1; //面積 double d = sx * sy; double c = (1 - sx) * sy; double b = sx * (1 - sy); double a = 1 - (d + c + b);// (1 - sx) * (1 - sy) //左上ピクセルの座標は //参照範囲の左上座標の小数部分を切り捨て(整数部分) //左上ピクセルのIndex int i = ((int)bpY * stride) + ((int)bpX * pByte); //値*面積 double aBlue = pixels[i] * a; double aGreen = pixels[i + 1] * a; double aRed = pixels[i + 2] * a; double bBlue = 0; double bGreen = 0; double bRed = 0; double cBlue = 0; double cGreen = 0; double cRed = 0; double dBlue = 0; double dGreen = 0; double dRed = 0; //B区以降は面積が0より大きいときだけ計算 if (b != 0) { //Aの右ピクセル*Bの面積 bBlue = pixels[i + pByte] * b; bGreen = pixels[i + pByte + 1] * b; bRed = pixels[i + pByte + 2] * b; } if (c != 0) { cBlue = pixels[i + stride] * c; cGreen = pixels[i + stride + 1] * c; cRed = pixels[i + stride + 2] * c; } if (d != 0) { //Aの右下ピクセル、仮にAが画像右下ピクセルだったとしても //そのときは面積が0のはずだからここは計算されない dBlue = pixels[i + stride + pByte] * d; dGreen = pixels[i + stride + pByte + 1] * d; dRed = pixels[i + stride + pByte + 2] * d; } //4区を合計して四捨五入で完成 resultPixels[y * scaledStride + x * pByte] = (byte)(aBlue + bBlue + cBlue + dBlue + 0.5); resultPixels[y * scaledStride + x * pByte + 1] = (byte)(aGreen + bGreen + cGreen + dGreen + 0.5); resultPixels[y * scaledStride + x * pByte + 2] = (byte)(aRed + bRed + cRed + dRed + 0.5); } }); BitmapSource bitmap = BitmapSource.Create(yoko, tate, 96, 96, source.Format, null, resultPixels, scaledStride); return bitmap; }
確認アプリのコード
作成動作環境
- Windows 10 Home バージョン 2004
- Visual Studio Community 2019
- WPF
- C#
- .NET 5
MainWindow.xaml
<Window x:Class="_20210416_Bilinear_24bitカラー専用.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:_20210416_Bilinear_24bitカラー専用" mc:Ignorable="d" Title="MainWindow" Height="450" Width="614" AllowDrop="True" Drop="Window_Drop"> <Grid> <DockPanel UseLayoutRounding="True"> <StackPanel DockPanel.Dock="Right"> <Button x:Name="MyButton1" Content="1/2倍" Click="MyButton1_Click"/> <Button x:Name="MyButton2" Content="1/3倍" Click="MyButton2_Click"/> <Button x:Name="MyButton3" Content="2倍" Click="MyButton3_Click"/> <Button x:Name="MyButton4" Content="3倍" Click="MyButton4_Click"/> <Button x:Name="MyButtonCopy" Content="コピー" Click="MyButtonCopy_Click" Margin="10"/> <Button x:Name="MyButtonPaste" Content="ペースト" Click="MyButtonPaste_Click" Margin="10"/> </StackPanel> <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto"> <Image x:Name="MyImage" Stretch="None"/> </ScrollViewer> </DockPanel> </Grid> </Window>
MainWindow.xaml.cs
using System; using System.Linq; using System.Threading.Tasks; using System.Windows; using System.Windows.Media; using System.Windows.Media.Imaging; namespace _20210416_Bilinear_24bitカラー専用 { public partial class MainWindow : Window { private BitmapSource MyBitmapOrigin; public MainWindow() { InitializeComponent(); #if DEBUG this.Top = 0; this.Left = 0; #endif } //縮小拡大対応完成版 /// <summary> /// 画像の拡大縮小、バイリニア法で補完(PixelFormats.Bgr24専用) /// </summary> /// <param name="source">PixelFormats.Bgr24のBitmap</param> /// <param name="yoko">横ピクセル数を指定</param> /// <param name="tate">縦ピクセル数を指定</param> /// <returns></returns> private BitmapSource BilinearBgr24専用(BitmapSource source, int yoko, int tate) { //元画像の画素値の配列作成 int sourceWidth = source.PixelWidth; int sourceHeight = source.PixelHeight; int stride = (sourceWidth * source.Format.BitsPerPixel + 7) / 8; byte[] pixels = new byte[sourceHeight * stride]; source.CopyPixels(pixels, stride, 0); //縮小後の画像の画素値の配列用 double yokoScale = (double)sourceWidth / yoko;//横倍率 double tateScale = (double)sourceHeight / tate; //1ピクセルあたりのバイト数、Byte / Pixel int pByte = (source.Format.BitsPerPixel + 7) / 8; int scaledStride = yoko * pByte; byte[] resultPixels = new byte[tate * scaledStride]; _ = Parallel.For(0, tate, y => { for (int x = 0; x < yoko; x++) { //参照範囲の左上座標bp double bpX = ((x + 0.5) * yokoScale) - 0.5; //画像範囲内チェック、参照範囲が画像から外れていたら修正(収める) if (bpX < 0) { bpX = 0; } if (bpX > sourceWidth - 1) { bpX = sourceWidth - 1; } double bpY = (y + 0.5) * tateScale - 0.5; if (bpY < 0) { bpY = 0; } if (bpY > sourceHeight - 1) { bpY = sourceHeight - 1; } //小数部分s double sx = bpX % 1; double sy = bpY % 1; //面積 double d = sx * sy; double c = (1 - sx) * sy; double b = sx * (1 - sy); double a = 1 - (d + c + b);// (1 - sx) * (1 - sy) //左上ピクセルの座標は //参照範囲の左上座標の小数部分を切り捨て(整数部分) //左上ピクセルのIndex int i = ((int)bpY * stride) + ((int)bpX * pByte); //値*面積 double aBlue = pixels[i] * a; double aGreen = pixels[i + 1] * a; double aRed = pixels[i + 2] * a; double bBlue = 0; double bGreen = 0; double bRed = 0; double cBlue = 0; double cGreen = 0; double cRed = 0; double dBlue = 0; double dGreen = 0; double dRed = 0; //B区以降は面積が0より大きいときだけ計算 if (b != 0) { //Aの右ピクセル*Bの面積 bBlue = pixels[i + pByte] * b; bGreen = pixels[i + pByte + 1] * b; bRed = pixels[i + pByte + 2] * b; } if (c != 0) { cBlue = pixels[i + stride] * c; cGreen = pixels[i + stride + 1] * c; cRed = pixels[i + stride + 2] * c; } if (d != 0) { //Aの右下ピクセル、仮にAが画像右下ピクセルだったとしても //そのときは面積が0のはずだからここは計算されない dBlue = pixels[i + stride + pByte] * d; dGreen = pixels[i + stride + pByte + 1] * d; dRed = pixels[i + stride + pByte + 2] * d; } //4区を合計して四捨五入で完成 resultPixels[y * scaledStride + x * pByte] = (byte)(aBlue + bBlue + cBlue + dBlue + 0.5); resultPixels[y * scaledStride + x * pByte + 1] = (byte)(aGreen + bGreen + cGreen + dGreen + 0.5); resultPixels[y * scaledStride + x * pByte + 2] = (byte)(aRed + bRed + cRed + dRed + 0.5); } }); BitmapSource bitmap = BitmapSource.Create(yoko, tate, 96, 96, source.Format, null, resultPixels, scaledStride); return bitmap; } //E:\オレ\エクセル\画像処理.xlsm_バイリニア法_$A$599 //縮小専用 /// <summary> /// 画像の縮小、バイリニア法で補完、PixelFormats.Bgr24専用) /// </summary> /// <param name="source">PixelFormats.Bgr24のBitmap</param> /// <param name="yoko">変換後の横ピクセル数を指定</param> /// <param name="tate">変換後の縦ピクセル数を指定</param> /// <returns></returns> private BitmapSource BilinearBgr24縮小専用(BitmapSource source, int yoko, int tate) { //元画像の画素値の配列作成 int sourceWidth = source.PixelWidth; int sourceHeight = source.PixelHeight; int stride = (sourceWidth * source.Format.BitsPerPixel + 7) / 8; byte[] pixels = new byte[sourceHeight * stride]; source.CopyPixels(pixels, stride, 0); //変換後の画像の画素値の配列用 double yokoScale = (double)sourceWidth / yoko;//横倍率 double tateScale = (double)sourceHeight / tate; //1ピクセルあたりのバイト数、Byte / Pixel int pByte = (source.Format.BitsPerPixel + 7) / 8; int scaledStride = yoko * pByte; byte[] resultPixels = new byte[tate * scaledStride]; _ = Parallel.For(0, tate, y => { for (int x = 0; x < yoko; x++) { //参照範囲の左上座標bp double bpX = ((x + 0.5) * yokoScale) - 0.5; double bpY = ((y + 0.5) * tateScale) - 0.5; //小数部分s double sx = bpX % 1; double sy = bpY % 1; //面積 double d = sx * sy; double c = (1 - sx) * sy; double b = sx * (1 - sy); double a = 1 - (d + c + b);// (1 - sx) * (1 - sy) //左上ピクセルの座標は //参照範囲の左上座標の小数部分を切り捨て(整数部分) //左上ピクセルのIndex int i = ((int)bpY * stride) + ((int)bpX * pByte); //各区の値*面積の合計を四捨五入して完成 //Blue resultPixels[y * scaledStride + x * pByte] = (byte)(pixels[i] * a + pixels[i + pByte] * b + pixels[i + stride] * c + pixels[i + stride + pByte] * d + 0.5); //Green resultPixels[y * scaledStride + x * pByte + 1] = (byte)(pixels[i + 1] * a + pixels[i + pByte + 1] * b + pixels[i + stride + 1] * c + pixels[i + stride + pByte + 1] * d + 0.5); //Red resultPixels[y * scaledStride + x * pByte + 2] = (byte)(pixels[i + 2] * a + pixels[i + pByte + 2] * b + pixels[i + stride + 2] * c + pixels[i + stride + pByte + 2] * d + 0.5); } }); BitmapSource bitmap = BitmapSource.Create(yoko, tate, 96, 96, source.Format, null, resultPixels, scaledStride); return bitmap; } /// <summary> /// 画像ファイルパスからPixelFormats.Bgr24のBitmapSource作成 /// </summary> /// <param name="filePath"></param> /// <param name="dpiX"></param> /// <param name="dpiY"></param> /// <returns></returns> private BitmapSource MakeBitmapSourceGray8FromFile(string filePath, double dpiX = 96, double dpiY = 96) { BitmapSource source = null; try { using (var stream = System.IO.File.OpenRead(filePath)) { source = BitmapFrame.Create(stream); if (source.Format != PixelFormats.Bgr24) { source = new FormatConvertedBitmap(source, PixelFormats.Bgr24, null, 0); } int w = source.PixelWidth; int h = source.PixelHeight; int stride = (w * source.Format.BitsPerPixel + 7) / 8; byte[] pixels = new byte[h * stride]; source.CopyPixels(pixels, stride, 0); source = BitmapSource.Create(w, h, dpiX, dpiY, source.Format, source.Palette, pixels, stride); }; } catch (Exception) { } return source; } //ファイルドロップ時 private void Window_Drop(object sender, DragEventArgs e) { if (e.Data.GetDataPresent(DataFormats.FileDrop) == false) return; //ファイルパス取得 var datas = (string[])e.Data.GetData(DataFormats.FileDrop); var paths = datas.ToList(); paths.Sort(); MyBitmapOrigin = MakeBitmapSourceGray8FromFile(paths[0]); MyImage.Source = MyBitmapOrigin; } //ボタンクリック private void MyButton1_Click(object sender, RoutedEventArgs e) { int yoko = (int)Math.Ceiling(MyBitmapOrigin.PixelWidth / 2.0); int tate = (int)Math.Ceiling(MyBitmapOrigin.PixelHeight / 2.0); MyImage.Source = BilinearBgr24縮小専用(MyBitmapOrigin, yoko, tate); } private void MyButton2_Click(object sender, RoutedEventArgs e) { int yoko = (int)Math.Ceiling(MyBitmapOrigin.PixelWidth / 3.0); int tate = (int)Math.Ceiling(MyBitmapOrigin.PixelHeight / 3.0); MyImage.Source = BilinearBgr24専用(MyBitmapOrigin, yoko, tate); } private void MyButton3_Click(object sender, RoutedEventArgs e) { MyImage.Source = BilinearBgr24専用(MyBitmapOrigin, MyBitmapOrigin.PixelWidth * 2, MyBitmapOrigin.PixelHeight * 2); } private void MyButton4_Click(object sender, RoutedEventArgs e) { MyImage.Source = BilinearBgr24専用(MyBitmapOrigin, MyBitmapOrigin.PixelWidth * 3, MyBitmapOrigin.PixelHeight * 3); } //画像をクリップボードにコピー private void MyButtonCopy_Click(object sender, RoutedEventArgs e) { Clipboard.SetImage((BitmapSource)MyImage.Source); } //クリップボードから画像追加 private void MyButtonPaste_Click(object sender, RoutedEventArgs e) { BitmapSource img = Clipboard.GetImage(); if (img != null) { MyBitmapOrigin = img; MyImage.Source = img; } } } }
確認アプリ
テスト画像
1/2倍
拡大
2倍
3倍
感想
カラー化はRGBそれぞれで、昨日と同じことするだけなので簡単にできた
24bitのカラー対応は単純にRGBそれぞれの処理を昨日のグレースケールと同じことをするから、処理量が3倍になるけどマルチスレッド化できたので、4コア以上のCPUなら昨日のより速いかも、とはいっても実用上では体感できなかった
各ピクセルの処理の順番は決まっていなから、マルチスレッド化もForをParallel.Forに置き換えただけでできたので、これもかんたんで拍子抜けだった
しかし...
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