mirror of
https://github.com/ShareX/ShareX.git
synced 2024-08-26 15:41:26 +12:00
145 lines
No EOL
5.1 KiB
C#
145 lines
No EOL
5.1 KiB
C#
#region License Information (GPL v3)
|
|
|
|
/*
|
|
ShareX - A program that allows you to take screenshots and share any file type
|
|
Copyright (c) 2007-2016 ShareX Team
|
|
|
|
This program is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU General Public License
|
|
as published by the Free Software Foundation; either version 2
|
|
of the License, or (at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
|
|
|
Optionally you can also view the license at <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#endregion License Information (GPL v3)
|
|
|
|
using System.Collections;
|
|
using System.Drawing;
|
|
using System.Drawing.Imaging;
|
|
|
|
namespace ShareX.HelpersLib
|
|
{
|
|
/// <summary>
|
|
/// Summary description for PaletteQuantizer.
|
|
/// </summary>
|
|
public class PaletteQuantizer : Quantizer
|
|
{
|
|
/// <summary>
|
|
/// Construct the palette quantizer
|
|
/// </summary>
|
|
/// <param name="palette">The color palette to quantize to</param>
|
|
/// <remarks>
|
|
/// Palette quantization only requires a single quantization step
|
|
/// </remarks>
|
|
public PaletteQuantizer(ArrayList palette)
|
|
: base(true)
|
|
{
|
|
_colorMap = new Hashtable();
|
|
|
|
_colors = new Color[palette.Count];
|
|
palette.CopyTo(_colors);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Override this to process the pixel in the second pass of the algorithm
|
|
/// </summary>
|
|
/// <param name="pixel">The pixel to quantize</param>
|
|
/// <returns>The quantized value</returns>
|
|
protected override byte QuantizePixel(Color32 pixel)
|
|
{
|
|
byte colorIndex = 0;
|
|
int colorHash = pixel.ARGB;
|
|
|
|
// Check if the color is in the lookup table
|
|
if (_colorMap.ContainsKey(colorHash))
|
|
colorIndex = (byte)_colorMap[colorHash];
|
|
else
|
|
{
|
|
// Not found - loop through the palette and find the nearest match.
|
|
// Firstly check the alpha value - if 0, lookup the transparent color
|
|
if (0 == pixel.Alpha)
|
|
{
|
|
// Transparent. Lookup the first color with an alpha value of 0
|
|
for (int index = 0; index < _colors.Length; index++)
|
|
{
|
|
if (0 == _colors[index].A)
|
|
{
|
|
colorIndex = (byte)index;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// Not transparent...
|
|
int leastDistance = int.MaxValue;
|
|
int red = pixel.Red;
|
|
int green = pixel.Green;
|
|
int blue = pixel.Blue;
|
|
|
|
// Loop through the entire palette, looking for the closest color match
|
|
for (int index = 0; index < _colors.Length; index++)
|
|
{
|
|
Color paletteColor = _colors[index];
|
|
|
|
int redDistance = paletteColor.R - red;
|
|
int greenDistance = paletteColor.G - green;
|
|
int blueDistance = paletteColor.B - blue;
|
|
|
|
int distance = (redDistance * redDistance) +
|
|
(greenDistance * greenDistance) +
|
|
(blueDistance * blueDistance);
|
|
|
|
if (distance < leastDistance)
|
|
{
|
|
colorIndex = (byte)index;
|
|
leastDistance = distance;
|
|
|
|
// And if it's an exact match, exit the loop
|
|
if (0 == distance)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Now I have the color, pop it into the hashtable for next time
|
|
_colorMap.Add(colorHash, colorIndex);
|
|
}
|
|
|
|
return colorIndex;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Retrieve the palette for the quantized image
|
|
/// </summary>
|
|
/// <param name="palette">Any old palette, this is overrwritten</param>
|
|
/// <returns>The new color palette</returns>
|
|
protected override ColorPalette GetPalette(ColorPalette palette)
|
|
{
|
|
for (int index = 0; index < _colors.Length; index++)
|
|
palette.Entries[index] = _colors[index];
|
|
|
|
return palette;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Lookup table for colors
|
|
/// </summary>
|
|
private Hashtable _colorMap;
|
|
|
|
/// <summary>
|
|
/// List of all colors in the palette
|
|
/// </summary>
|
|
protected Color[] _colors;
|
|
}
|
|
} |