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Diffstat (limited to 'kpdf/xpdf/splash/SplashScreen.cc')
| -rw-r--r-- | kpdf/xpdf/splash/SplashScreen.cc | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/kpdf/xpdf/splash/SplashScreen.cc b/kpdf/xpdf/splash/SplashScreen.cc new file mode 100644 index 00000000..3e8d36ca --- /dev/null +++ b/kpdf/xpdf/splash/SplashScreen.cc @@ -0,0 +1,385 @@ +//======================================================================== +// +// SplashScreen.cc +// +//======================================================================== + +#include <aconf.h> + +#ifdef USE_GCC_PRAGMAS +#pragma implementation +#endif + +#include <stdlib.h> +#include <string.h> +#include "gmem.h" +#include "SplashMath.h" +#include "SplashScreen.h" + +//------------------------------------------------------------------------ + +static SplashScreenParams defaultParams = { + splashScreenDispersed, // type + 2, // size + 2, // dotRadius + 1.0, // gamma + 0.0, // blackThreshold + 1.0 // whiteThreshold +}; + +//------------------------------------------------------------------------ + +struct SplashScreenPoint { + int x, y; + int dist; +}; + +static int cmpDistances(const void *p0, const void *p1) { + return ((SplashScreenPoint *)p0)->dist - ((SplashScreenPoint *)p1)->dist; +} + +//------------------------------------------------------------------------ +// SplashScreen +//------------------------------------------------------------------------ + +// If <clustered> is true, this generates a 45 degree screen using a +// circular dot spot function. DPI = resolution / ((size / 2) * +// sqrt(2)). If <clustered> is false, this generates an optimal +// threshold matrix using recursive tesselation. Gamma correction +// (gamma = 1 / 1.33) is also computed here. +SplashScreen::SplashScreen(SplashScreenParams *params) { + Guchar u, black, white; + int i; + + if (!params) { + params = &defaultParams; + } + + switch (params->type) { + + case splashScreenDispersed: + // size must be a power of 2 + for (size = 1; size < params->size; size <<= 1) ; + mat = (Guchar *)gmallocn(size * size, sizeof(Guchar)); + buildDispersedMatrix(size/2, size/2, 1, size/2, 1); + break; + + case splashScreenClustered: + // size must be even + size = (params->size >> 1) << 1; + if (size < 2) { + size = 2; + } + mat = (Guchar *)gmallocn(size * size, sizeof(Guchar)); + buildClusteredMatrix(); + break; + + case splashScreenStochasticClustered: + // size must be at least 2*r + if (params->size < 2 * params->dotRadius) { + size = 2 * params->dotRadius; + } else { + size = params->size; + } + mat = (Guchar *)gmallocn(size * size, sizeof(Guchar)); + buildSCDMatrix(params->dotRadius); + break; + } + + // do gamma correction and compute minVal/maxVal + minVal = 255; + maxVal = 0; + black = splashRound((SplashCoord)255.0 * params->blackThreshold); + if (black < 1) { + black = 1; + } + int whiteAux = splashRound((SplashCoord)255.0 * params->whiteThreshold); + if (whiteAux > 255) { + white = 255; + } else { + white = whiteAux; + } + for (i = 0; i < size * size; ++i) { + u = splashRound((SplashCoord)255.0 * + splashPow((SplashCoord)mat[i] / 255.0, params->gamma)); + if (u < black) { + u = black; + } else if (u >= white) { + u = white; + } + mat[i] = u; + if (u < minVal) { + minVal = u; + } else if (u > maxVal) { + maxVal = u; + } + } +} + +void SplashScreen::buildDispersedMatrix(int i, int j, int val, + int delta, int offset) { + if (delta == 0) { + // map values in [1, size^2] --> [1, 255] + mat[i * size + j] = 1 + (254 * (val - 1)) / (size * size - 1); + } else { + buildDispersedMatrix(i, j, + val, delta / 2, 4*offset); + buildDispersedMatrix((i + delta) % size, (j + delta) % size, + val + offset, delta / 2, 4*offset); + buildDispersedMatrix((i + delta) % size, j, + val + 2*offset, delta / 2, 4*offset); + buildDispersedMatrix((i + 2*delta) % size, (j + delta) % size, + val + 3*offset, delta / 2, 4*offset); + } +} + +void SplashScreen::buildClusteredMatrix() { + SplashCoord *dist; + SplashCoord u, v, d; + Guchar val; + int size2, x, y, x1, y1, i; + + size2 = size >> 1; + + // initialize the threshold matrix + for (y = 0; y < size; ++y) { + for (x = 0; x < size; ++x) { + mat[y * size + x] = 0; + } + } + + // build the distance matrix + dist = (SplashCoord *)gmallocn(size * size2, sizeof(SplashCoord)); + for (y = 0; y < size2; ++y) { + for (x = 0; x < size2; ++x) { + if (x + y < size2 - 1) { + u = (SplashCoord)x + 0.5 - 0; + v = (SplashCoord)y + 0.5 - 0; + } else { + u = (SplashCoord)x + 0.5 - (SplashCoord)size2; + v = (SplashCoord)y + 0.5 - (SplashCoord)size2; + } + dist[y * size2 + x] = u*u + v*v; + } + } + for (y = 0; y < size2; ++y) { + for (x = 0; x < size2; ++x) { + if (x < y) { + u = (SplashCoord)x + 0.5 - 0; + v = (SplashCoord)y + 0.5 - (SplashCoord)size2; + } else { + u = (SplashCoord)x + 0.5 - (SplashCoord)size2; + v = (SplashCoord)y + 0.5 - 0; + } + dist[(size2 + y) * size2 + x] = u*u + v*v; + } + } + + // build the threshold matrix + minVal = 1; + maxVal = 0; + x1 = y1 = 0; // make gcc happy + for (i = 0; i < size * size2; ++i) { + d = -1; + for (y = 0; y < size; ++y) { + for (x = 0; x < size2; ++x) { + if (mat[y * size + x] == 0 && + dist[y * size2 + x] > d) { + x1 = x; + y1 = y; + d = dist[y1 * size2 + x1]; + } + } + } + // map values in [0, 2*size*size2-1] --> [1, 255] + val = 1 + (254 * (2*i)) / (2*size*size2 - 1); + mat[y1 * size + x1] = val; + val = 1 + (254 * (2*i+1)) / (2*size*size2 - 1); + if (y1 < size2) { + mat[(y1 + size2) * size + x1 + size2] = val; + } else { + mat[(y1 - size2) * size + x1 + size2] = val; + } + } + + gfree(dist); +} + +// Compute the distance between two points on a toroid. +int SplashScreen::distance(int x0, int y0, int x1, int y1) { + int dx0, dx1, dx, dy0, dy1, dy; + + dx0 = abs(x0 - x1); + dx1 = size - dx0; + dx = dx0 < dx1 ? dx0 : dx1; + dy0 = abs(y0 - y1); + dy1 = size - dy0; + dy = dy0 < dy1 ? dy0 : dy1; + return dx * dx + dy * dy; +} + +// Algorithm taken from: +// Victor Ostromoukhov and Roger D. Hersch, "Stochastic Clustered-Dot +// Dithering" in Color Imaging: Device-Independent Color, Color +// Hardcopy, and Graphic Arts IV, SPIE Vol. 3648, pp. 496-505, 1999. +void SplashScreen::buildSCDMatrix(int r) { + SplashScreenPoint *dots, *pts; + int dotsLen, dotsSize; + char *tmpl; + char *grid; + int *region, *dist; + int x, y, xx, yy, x0, x1, y0, y1, i, j, d, iMin, dMin, n; + + //~ this should probably happen somewhere else + srand(123); + + // generate the random space-filling curve + pts = (SplashScreenPoint *)gmallocn(size * size, sizeof(SplashScreenPoint)); + i = 0; + for (y = 0; y < size; ++y) { + for (x = 0; x < size; ++x) { + pts[i].x = x; + pts[i].y = y; + ++i; + } + } + for (i = 0; i < size * size; ++i) { + j = i + (int)((double)(size * size - i) * + (double)rand() / ((double)RAND_MAX + 1.0)); + x = pts[i].x; + y = pts[i].y; + pts[i].x = pts[j].x; + pts[i].y = pts[j].y; + pts[j].x = x; + pts[j].y = y; + } + + // construct the circle template + tmpl = (char *)gmallocn((r+1)*(r+1), sizeof(char)); + for (y = 0; y <= r; ++y) { + for (x = 0; x <= r; ++x) { + tmpl[y*(r+1) + x] = (x * y <= r * r) ? 1 : 0; + } + } + + // mark all grid cells as free + grid = (char *)gmallocn(size * size, sizeof(char)); + for (y = 0; y < size; ++y) { + for (x = 0; x < size; ++x) { + grid[y*size + x] = 0; + } + } + + // walk the space-filling curve, adding dots + dotsLen = 0; + dotsSize = 32; + dots = (SplashScreenPoint *)gmallocn(dotsSize, sizeof(SplashScreenPoint)); + for (i = 0; i < size * size; ++i) { + x = pts[i].x; + y = pts[i].y; + if (!grid[y*size + x]) { + if (dotsLen == dotsSize) { + dotsSize *= 2; + dots = (SplashScreenPoint *)greallocn(dots, dotsSize, + sizeof(SplashScreenPoint)); + } + dots[dotsLen++] = pts[i]; + for (yy = 0; yy <= r; ++yy) { + y0 = (y + yy) % size; + y1 = (y - yy + size) % size; + for (xx = 0; xx <= r; ++xx) { + if (tmpl[yy*(r+1) + xx]) { + x0 = (x + xx) % size; + x1 = (x - xx + size) % size; + grid[y0*size + x0] = 1; + grid[y0*size + x1] = 1; + grid[y1*size + x0] = 1; + grid[y1*size + x1] = 1; + } + } + } + } + } + + gfree(tmpl); + gfree(grid); + + // assign each cell to a dot, compute distance to center of dot + region = (int *)gmallocn(size * size, sizeof(int)); + dist = (int *)gmallocn(size * size, sizeof(int)); + for (y = 0; y < size; ++y) { + for (x = 0; x < size; ++x) { + iMin = 0; + dMin = distance(dots[0].x, dots[0].y, x, y); + for (i = 1; i < dotsLen; ++i) { + d = distance(dots[i].x, dots[i].y, x, y); + if (d < dMin) { + iMin = i; + dMin = d; + } + } + region[y*size + x] = iMin; + dist[y*size + x] = dMin; + } + } + + // compute threshold values + for (i = 0; i < dotsLen; ++i) { + n = 0; + for (y = 0; y < size; ++y) { + for (x = 0; x < size; ++x) { + if (region[y*size + x] == i) { + pts[n].x = x; + pts[n].y = y; + pts[n].dist = distance(dots[i].x, dots[i].y, x, y); + ++n; + } + } + } + qsort(pts, n, sizeof(SplashScreenPoint), &cmpDistances); + for (j = 0; j < n; ++j) { + // map values in [0 .. n-1] --> [255 .. 1] + mat[pts[j].y * size + pts[j].x] = 255 - (254 * j) / (n - 1); + } + } + + gfree(pts); + gfree(region); + gfree(dist); + + gfree(dots); +} + +SplashScreen::SplashScreen(SplashScreen *screen) { + size = screen->size; + mat = (Guchar *)gmallocn(size * size, sizeof(Guchar)); + memcpy(mat, screen->mat, size * size * sizeof(Guchar)); + minVal = screen->minVal; + maxVal = screen->maxVal; +} + +SplashScreen::~SplashScreen() { + gfree(mat); +} + +int SplashScreen::test(int x, int y, Guchar value) { + int xx, yy; + + if (value < minVal) { + return 0; + } + if (value >= maxVal) { + return 1; + } + if ((xx = x % size) < 0) { + xx = -xx; + } + if ((yy = y % size) < 0) { + yy = -yy; + } + return value < mat[yy * size + xx] ? 0 : 1; +} + +GBool SplashScreen::isStatic(Guchar value) { + return value < minVal || value >= maxVal; +} |