Edited at

塗りつぶし実装してみた(C#)


やりたいこと

以前作成したC#で画像からWindowsアイコン(.ico)に変換するソフトつくった - 透過対応を実際に使ってみた際に、元画像にアンチエイリアシングかかってると透過部分の見た目がイケてない感じになったので、連続的に透過させたい。

※塗りつぶしはできたが、「連続的に」は、まだです。そのうちやります。。


アイデア

塗りつぶし対象色と各画素の、色間の距離を適当に定義して、それを元にアルファ値とRGBを設定すればできそう。


はまった点

透過処理したのに透過bitmapにならない

⇒Bitmapを画像ファイルから読み込んだときのPixelFormatにひきずられていた。

塗りつぶしアルゴリズム

⇒単純に面倒でした・・・

塗りつぶしアルゴリズムの図解

image.png



状況

■やれていないこと

・alphaがまだ固定値です。そのうち更新します。

■やれていること

・塗りつぶしができた

・塗りつぶした箇所を透過にできた


ソースコード

ToDo: デバッグ用にtestin.bmpを読み込むようにしているので、そのうち直す。

using System;

using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Windows.Forms;

class MainForm:Form
{
ToolTip toolTip;
SplitContainer spl;
PictureBox pct;
NumericUpDown nudZoom;
TrackBar barBackColorWhiteness;
Bitmap bmpOrg;

const int THRESH = 10;
const byte FILLED = 1; // 塗りつぶし済みマーク用の値

// ToDo: RBGより他の色体系を使った方が画像が綺麗にできそう

// thre >= 0
static bool IsToBeFilled(Color tgt, Color c, int thre)
{
int dr = (int)tgt.R - (int)c.R;
int dg = (int)tgt.G - (int)c.G;
int db = (int)tgt.B - (int)c.B;

return ( -thre <= dr && dr <= thre &&
-thre <= dg && dg <= thre &&
-thre <= db && db <= thre ) ;
}

// 次にscanすべき線分を探して登録する
unsafe static void ScanLine( Stack<Point> stack, byte* ptr, int lx, int rx, int y, Color tgtColor, int thre)
{
bool continuousPixel = false;
for ( int x=lx ; x<=rx ; x++ ) {
Color curColor = GetColor32bit(ptr + 4*x);
if ( IsToBeFilled(tgtColor, curColor, thre) ) {
if (!continuousPixel) {
stack.Push(new Point(x,y));
continuousPixel = true;
}
}
else {
continuousPixel = false;
}
}
}

unsafe static Color GetColor32bit(byte* ptr)
{
return Color.FromArgb(ptr[3],ptr[2],ptr[1],ptr[0]);
}

static Bitmap Fill32bppBitmapToData(Bitmap bmp, Point startPoint, int thre)
{
if ( startPoint.X<0 || startPoint.X>=bmp.Width ||
startPoint.Y<0 || startPoint.Y>=bmp.Height ) {
return bmp;
}

var stack = new Stack<Point>();
byte[,] fillMark = new byte[bmp.Width, bmp.Height];

BitmapData bdSrc = bmp.LockBits(new Rectangle(0,0,bmp.Width,bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
Bitmap bmpDest = null;

try {
bmpDest = new Bitmap(bmp.Width, bmp.Height, PixelFormat.Format32bppArgb); // PixelFormat.Format32bppArgbのbitmapを作るため
BitmapData bdDest = bmpDest.LockBits(new Rectangle(0,0,bmpDest.Width,bmpDest.Height), ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
try {
unsafe {
byte* ptr = (byte*)bdSrc.Scan0;
Color targetColor = GetColor32bit( ptr + startPoint.Y*bdSrc.Stride + 4*startPoint.X );

stack.Push(startPoint);

while ( stack.Count > 0 ) {
Point curP = stack.Pop();
if ( fillMark[curP.X, curP.Y] == FILLED ) {continue;}

int lx = curP.X;
int rx = curP.X;

for (int x = curP.X+1; x<bmp.Width; x++) {
Color curColor = GetColor32bit(ptr + curP.Y*bdSrc.Stride + 4*x);

if ( IsToBeFilled(targetColor, curColor, thre) ) {
fillMark[x, curP.Y] = FILLED;
}
else{
break;
}
rx = x;
}
for (int x = curP.X; x>=0; x--) {
Color curColor = GetColor32bit(ptr + curP.Y*bdSrc.Stride + 4*x);

if ( IsToBeFilled(targetColor, curColor, thre) ) {
fillMark[x, curP.Y] = FILLED;
}
else{
break;
}
lx = x;
}

if ( curP.Y > 0 ) {
ScanLine( stack, ptr + (curP.Y-1) * bdSrc.Stride, lx, rx, curP.Y-1, targetColor, thre);
}
if ( curP.Y < bmp.Height - 1 ) {
ScanLine( stack, ptr + (curP.Y+1) * bdSrc.Stride, lx, rx, curP.Y+1, targetColor, thre);
}
}

// 書き込み
byte* ptrDest = (byte*)bdDest.Scan0;
for ( int y=0 ; y<bmp.Height ; y++ ) {
for ( int x=0 ; x<bmp.Width ; x++ ) {
ptrDest[y*bdDest.Stride + 4*x ] = ptr[y*bdSrc.Stride + 4*x ];
ptrDest[y*bdDest.Stride + 4*x + 1] = ptr[y*bdSrc.Stride + 4*x + 1];
ptrDest[y*bdDest.Stride + 4*x + 2] = ptr[y*bdSrc.Stride + 4*x + 2];
if ( fillMark[x,y] == FILLED ) {
ptrDest[y*bdDest.Stride + 4*x + 3] = 0;// alpha = 0 (透過)
}
else {
ptrDest[y*bdDest.Stride + 4*x + 3] = ptr[y*bdSrc.Stride + 4*x + 3];
}
}
}
}
}
finally {
bmpDest.UnlockBits(bdDest);
}
}
finally {
bmp.UnlockBits(bdSrc);
}

// for debug
// bmpDest.Save("test.png", System.Drawing.Imaging.ImageFormat.Png);

return bmpDest;
}

MainForm(string file)
{
toolTip = new ToolTip();
var menu = new MenuStrip();

var menuItemFile = new ToolStripMenuItem("&File");
menu.Items.Add(menuItemFile);
var menuItemFileOpen = new ToolStripMenuItem("Open ...", null, (sender,e)=>FileOpen(), "FileOpen");
menuItemFile.DropDownItems.Add(menuItemFileOpen);
var menuItemFileSaveAs = new ToolStripMenuItem("SaveAs ...", null, (sender,e)=>FileSaveAs(), "FileSaveAs");
menuItemFile.DropDownItems.Add(menuItemFileSaveAs);

var menuItemEdit = new ToolStripMenuItem("&Edit");
menu.Items.Add(menuItemEdit);
var menuItemEditPaste = new ToolStripMenuItem("Paste from clipboard", null, (sender,e)=>PasteFromClipboard(), "EditPaste");
menuItemEdit.DropDownItems.Add(menuItemEditPaste);
var menuItemEditCopy = new ToolStripMenuItem("Copy to clipboard", null, (sender,e)=>CopyToClipboard(), "EditCopy");
menuItemEdit.DropDownItems.Add(menuItemEditCopy);

Controls.Add(menu);

spl = new SplitContainer();
spl.Location = new Point(0, 30);
// spl.Dock = DockStyle.Fill;
spl.Orientation = Orientation.Horizontal;
Controls.Add(spl);

nudZoom = new NumericUpDown();
nudZoom.Maximum = 10;
nudZoom.Value = 2;
nudZoom.Minimum = 1;
nudZoom.ValueChanged += (sender,e)=>{RedrawPct();};
nudZoom.Width = 50;
toolTip.SetToolTip(nudZoom, "Zoom");
spl.Panel1.Controls.Add(nudZoom);

barBackColorWhiteness = new TrackBar();
barBackColorWhiteness.Location = new Point(60,0);
barBackColorWhiteness.Maximum = 255;
barBackColorWhiteness.Value = 255;
barBackColorWhiteness.Minimum = 0;
barBackColorWhiteness.TickFrequency = 51;
barBackColorWhiteness.ValueChanged += (sender,e)=>{RedrawPct();};
toolTip.SetToolTip(barBackColorWhiteness, "Background Color Whiteness");
spl.Panel1.Controls.Add(barBackColorWhiteness);

bmpOrg = new Bitmap(10,10,PixelFormat.Format32bppArgb); // dummy to avoid null
try {
bmpOrg = (Bitmap)Bitmap.FromFile(file);
}
catch (IOException){
}

pct = new PictureBox();
pct.Dock = DockStyle.Fill;
spl.Panel2.Controls.Add(pct);

spl.IsSplitterFixed = true;

RedrawPct();

pct.MouseDown += Pct_MouseDown;
Resize += Form_Resize;
ResizeEnd += Form_Resize;
Load += Form_Resize;
}

void Form_Resize(object sender, EventArgs e)
{
int h = ClientSize.Height - spl.Top;
spl.Size = new System.Drawing.Size(ClientSize.Width, (h>1)?h:1);
spl.SplitterDistance = barBackColorWhiteness.Bottom;
}

void Pct_MouseDown(object sender, MouseEventArgs e)
{
int zoom = (int)nudZoom.Value;
Point p = new Point(e.X/zoom, e.Y/zoom);
bmpOrg = Fill32bppBitmapToData(bmpOrg, p, 10);
RedrawPct();
}

void RedrawPct()
{
int zoom = (int)nudZoom.Value;
int bgc = (int)barBackColorWhiteness.Value;
Bitmap bmp = new Bitmap(bmpOrg.Width*zoom, bmpOrg.Height*zoom, PixelFormat.Format32bppArgb);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.FromArgb(bgc,bgc,bgc));
g.InterpolationMode = InterpolationMode.NearestNeighbor;
g.PixelOffsetMode = PixelOffsetMode.Half;
g.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceOver;
g.DrawImage(bmpOrg, 0, 0, bmp.Width, bmp.Height);
pct.Image = bmp;
}

void FileOpen()
{
var dlg = new OpenFileDialog();
// dlg.FileName = "xxx.png";
// dlg.InitialDirectory = @"C:\";
dlg.Filter = "Image file(*.png;*.bmp)|*.png;*.bmp|All file(*.*)|*.*";
dlg.FilterIndex = 1;
dlg.Title = "Select file to open";
dlg.RestoreDirectory = true;
// dlg.CheckFileExists = true;
// dlg.CheckPathExists = true;

if ( dlg.ShowDialog() == DialogResult.OK ) {
Bitmap tmp = null;
try {
tmp = (Bitmap)Bitmap.FromFile(dlg.FileName);
}
catch (OutOfMemoryException e) { MessageBox.Show(e.ToString()); }
catch (FileNotFoundException e) { MessageBox.Show(e.ToString()); }
catch (InvalidCastException e) { MessageBox.Show(e.ToString()); }

if ( tmp != null ) {
bmpOrg = tmp;
RedrawPct();
}
}
}
void FileSaveAs()
{
SaveFileDialog dlg = new SaveFileDialog();

dlg.FileName = "test.png";
//dlg.InitialDirectory = @"C:\";
dlg.Filter = "PNG file(*.png)|*.png";
dlg.FilterIndex = 1;
dlg.Title = "Select file name to save";
dlg.RestoreDirectory = true;
//dlg.OverwritePrompt = true;
//dlg.CheckPathExists = true;

if ( dlg.ShowDialog() == DialogResult.OK ) {
bmpOrg.Save(dlg.FileName, System.Drawing.Imaging.ImageFormat.Png);
}
}
void CopyToClipboard()
{
Clipboard.SetImage(bmpOrg);
}
void PasteFromClipboard()
{
Bitmap tmp = null;
try {
tmp = (Bitmap)(Image)Clipboard.GetData(DataFormats.Bitmap);
}
catch (Exception e) {
MessageBox.Show(e.ToString());
}

if ( tmp != null ) {
bmpOrg = tmp;
RedrawPct();
}
}

[STAThread]
static void Main(string[] args)
{
Application.Run(new MainForm("testin.bmp"));
}
}


参考サイト