1//========================================================================
2//
3// SplashScreen.h
4//
5//========================================================================
6
7//========================================================================
8//
9// Modified under the Poppler project - http://poppler.freedesktop.org
10//
11// All changes made under the Poppler project to this file are licensed
12// under GPL version 2 or later
13//
14// Copyright (C) 2009, 2018, 2020, 2021 Albert Astals Cid <aacid@kde.org>
15//
16// To see a description of the changes please see the Changelog file that
17// came with your tarball or type make ChangeLog if you are building from git
18//
19//========================================================================
20
21#ifndef SPLASHSCREEN_H
22#define SPLASHSCREEN_H
23
24#include "SplashTypes.h"
25
26#include <cstdlib>
27
28//------------------------------------------------------------------------
29// SplashScreen
30//------------------------------------------------------------------------
31
32class SplashScreen
33{
34public:
35 explicit SplashScreen(const SplashScreenParams *params);
36 explicit SplashScreen(const SplashScreen *screen);
37 ~SplashScreen();
38
39 SplashScreen(const SplashScreen &) = delete;
40 SplashScreen &operator=(const SplashScreen &) = delete;
41
42 SplashScreen *copy() const { return new SplashScreen(this); }
43
44 // Return the computed pixel value (0=black, 1=white) for the gray
45 // level <value> at (<x>, <y>).
46 int test(int x, int y, unsigned char value)
47 {
48 int xx, yy;
49 if (mat == nullptr) {
50 createMatrix();
51 }
52 xx = x & sizeM1;
53 yy = y & sizeM1;
54 return value < mat[(yy << log2Size) + xx] ? 0 : 1;
55 }
56
57 // Returns true if value is above the white threshold or below the
58 // black threshold, i.e., if the corresponding halftone will be
59 // solid white or black.
60 bool isStatic(unsigned char value)
61 {
62 if (mat == nullptr) {
63 createMatrix();
64 }
65 return value < minVal || value >= maxVal;
66 }
67
68private:
69 void createMatrix();
70
71 void buildDispersedMatrix(int i, int j, int val, int delta, int offset);
72 void buildClusteredMatrix();
73 int distance(int x0, int y0, int x1, int y1);
74 void buildSCDMatrix(int r);
75
76 const SplashScreenParams *screenParams; // params to create the other members
77 unsigned char *mat; // threshold matrix
78 int size; // size of the threshold matrix
79 int sizeM1; // size - 1
80 int log2Size; // log2(size)
81 unsigned char minVal; // any pixel value below minVal generates
82 // solid black
83 unsigned char maxVal; // any pixel value above maxVal generates
84 // solid white
85};
86
87#endif
88

source code of poppler/splash/SplashScreen.h