image.cpp
/*
* This file is part of the KDE libraries
* Copyright (c) 2001 Michael Goffioul <kdeprint@swing.be>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License version 2 as published by the Free Software Foundation.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
**/
#include <qimage.h>
#include <math.h>
void
mult(float a[3][3], /* I - First matrix */
float b[3][3], /* I - Second matrix */
float c[3][3]) /* I - Destination matrix */
{
int x, y; /* Looping vars */
float temp[3][3]; /* Temporary matrix */
/*
* Multiply a and b, putting the result in temp...
*/
for (y = 0; y < 3; y ++)
for (x = 0; x < 3; x ++)
temp[y][x] = b[y][0] * a[0][x] +
b[y][1] * a[1][x] +
b[y][2] * a[2][x];
/*
* Copy temp to c (that way c can be a pointer to a or b).
*/
memcpy(c, temp, sizeof(temp));
}
void
saturate(float mat[3][3], /* I - Matrix to append to */
float sat) /* I - Desired color saturation */
{
float smat[3][3]; /* Saturation matrix */
smat[0][0] = (1.0 - sat) * 0.3086 + sat;
smat[0][1] = (1.0 - sat) * 0.3086;
smat[0][2] = (1.0 - sat) * 0.3086;
smat[1][0] = (1.0 - sat) * 0.6094;
smat[1][1] = (1.0 - sat) * 0.6094 + sat;
smat[1][2] = (1.0 - sat) * 0.6094;
smat[2][0] = (1.0 - sat) * 0.0820;
smat[2][1] = (1.0 - sat) * 0.0820;
smat[2][2] = (1.0 - sat) * 0.0820 + sat;
mult(smat, mat, mat);
}
void
xform(float mat[3][3], /* I - Matrix */
float x, /* I - Input X coordinate */
float y, /* I - Input Y coordinate */
float z, /* I - Input Z coordinate */
float *tx, /* O - Output X coordinate */
float *ty, /* O - Output Y coordinate */
float *tz) /* O - Output Z coordinate */
{
*tx = x * mat[0][0] + y * mat[1][0] + z * mat[2][0];
*ty = x * mat[0][1] + y * mat[1][1] + z * mat[2][1];
*tz = x * mat[0][2] + y * mat[1][2] + z * mat[2][2];
}
void
xrotate(float mat[3][3], /* I - Matrix */
float rs, /* I - Rotation angle sine */
float rc) /* I - Rotation angle cosine */
{
float rmat[3][3]; /* I - Rotation matrix */
rmat[0][0] = 1.0;
rmat[0][1] = 0.0;
rmat[0][2] = 0.0;
rmat[1][0] = 0.0;
rmat[1][1] = rc;
rmat[1][2] = rs;
rmat[2][0] = 0.0;
rmat[2][1] = -rs;
rmat[2][2] = rc;
mult(rmat, mat, mat);
}
void
yrotate(float mat[3][3], /* I - Matrix */
float rs, /* I - Rotation angle sine */
float rc) /* I - Rotation angle cosine */
{
float rmat[3][3]; /* I - Rotation matrix */
rmat[0][0] = rc;
rmat[0][1] = 0.0;
rmat[0][2] = -rs;
rmat[1][0] = 0.0;
rmat[1][1] = 1.0;
rmat[1][2] = 0.0;
rmat[2][0] = rs;
rmat[2][1] = 0.0;
rmat[2][2] = rc;
mult(rmat,mat,mat);
}
void
zrotate(float mat[3][3], /* I - Matrix */
float rs, /* I - Rotation angle sine */
float rc) /* I - Rotation angle cosine */
{
float rmat[3][3]; /* I - Rotation matrix */
rmat[0][0] = rc;
rmat[0][1] = rs;
rmat[0][2] = 0.0;
rmat[1][0] = -rs;
rmat[1][1] = rc;
rmat[1][2] = 0.0;
rmat[2][0] = 0.0;
rmat[2][1] = 0.0;
rmat[2][2] = 1.0;
mult(rmat,mat,mat);
}
void
zshear(float mat[3][3], /* I - Matrix */
float dx, /* I - X shear */
float dy) /* I - Y shear */
{
float smat[3][3]; /* Shear matrix */
smat[0][0] = 1.0;
smat[0][1] = 0.0;
smat[0][2] = dx;
smat[1][0] = 0.0;
smat[1][1] = 1.0;
smat[1][2] = dy;
smat[2][0] = 0.0;
smat[2][1] = 0.0;
smat[2][2] = 1.0;
mult(smat, mat, mat);
}
void
huerotate(float mat[3][3], /* I - Matrix to append to */
float rot) /* I - Hue rotation in degrees */
{
float hmat[3][3] = {{1.0,0.0,0.0},{0.0,1.0,0.0},{0.0,0.0,1.0}}; /* Hue matrix */
float lx, ly, lz; /* Luminance vector */
float xrs, xrc; /* X rotation sine/cosine */
float yrs, yrc; /* Y rotation sine/cosine */
float zrs, zrc; /* Z rotation sine/cosine */
float zsx, zsy; /* Z shear x/y */
/*
* Rotate the gray vector into positive Z...
*/
xrs = M_SQRT1_2;
xrc = M_SQRT1_2;
xrotate(hmat,xrs,xrc);
yrs = -1.0 / sqrt(3.0);
yrc = -M_SQRT2 * yrs;
yrotate(hmat,yrs,yrc);
/*
* Shear the space to make the luminance plane horizontal...
*/
xform(hmat, 0.3086, 0.6094, 0.0820, &lx, &ly, &lz);
zsx = lx / lz;
zsy = ly / lz;
zshear(hmat, zsx, zsy);
/*
* Rotate the hue...
*/
zrs = sin(rot * M_PI / 180.0);
zrc = cos(rot * M_PI / 180.0);
zrotate(hmat, zrs, zrc);
/*
* Unshear the space to put the luminance plane back...
*/
zshear(hmat, -zsx, -zsy);
/*
* Rotate the gray vector back into place...
*/
yrotate(hmat, -yrs, yrc);
xrotate(hmat, -xrs, xrc);
/*
* Append it to the current matrix...
*/
mult(hmat, mat, mat);
}
void
bright(float mat[3][3],
float scale)
{
for (int i=0;i<3;i++)
for (int j=0;j<3;j++)
mat[i][j] *= scale;
}
//----------------------------------------------------------------------------------------------------
QImage convertImage(const QImage& image, int hue, int saturation, int brightness, int gamma)
{
float mat[3][3] = {{1.0,0.0,0.0},{0.0,1.0,0.0},{0.0,0.0,1.0}};
int lut[3][3][256];
QRgb c;
int r,g,b,v,r2,g2,b2;
float gam = 1.0/(float(gamma)/1000.0);
QImage img(image);
saturate(mat,saturation*0.01);
huerotate(mat,(float)hue);
bright(mat,brightness*0.01);
for (int i = 0; i < 3; i ++)
for (int j = 0; j < 3; j ++)
for (int k = 0; k < 256; k ++)
lut[i][j][k] = (int)(mat[i][j] * k + 0.5);
img.detach();
for (int i=0;i<image.width();i++)
for (int j=0;j<image.height();j++)
{
c = image.pixel(i,j);
r = qRed(c);
g = qGreen(c);
b = qBlue(c);
v = lut[0][0][r] + lut[1][0][g] + lut[2][0][b];
if (gamma != 1000) v = (int)rint(pow(v,gam));
if (v < 0) r2 = 0;
else if (v > 255) r2 = 255;
else r2 = v;
v = lut[0][1][r] + lut[1][1][g] + lut[2][1][b];
if (gamma != 1000) v = (int)rint(pow(v,gam));
if (v < 0) g2 = 0;
else if (v > 255) g2 = 255;
else g2 = v;
v = lut[0][2][r] + lut[1][2][g] + lut[2][2][b];
if (gamma != 1000) v = (int)rint(pow(v,gam));
if (v < 0) b2 = 0;
else if (v > 255) b2 = 255;
else b2 = v;
img.setPixel(i,j,qRgb(r2,g2,b2));
}
return img;
}

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