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 
32 class SplashScreen
33 {
34 public:
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 
copy()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>).
test(int x,int y,unsigned char value)46     int test(int x, int y, unsigned char value)
47     {
48         int xx, yy;
49         if (mat == nullptr)
50             createMatrix();
51         xx = x & sizeM1;
52         yy = y & sizeM1;
53         return value < mat[(yy << log2Size) + xx] ? 0 : 1;
54     }
55 
56     // Returns true if value is above the white threshold or below the
57     // black threshold, i.e., if the corresponding halftone will be
58     // solid white or black.
isStatic(unsigned char value)59     bool isStatic(unsigned char value)
60     {
61         if (mat == nullptr)
62             createMatrix();
63         return value < minVal || value >= maxVal;
64     }
65 
66 private:
67     void createMatrix();
68 
69     void buildDispersedMatrix(int i, int j, int val, int delta, int offset);
70     void buildClusteredMatrix();
71     int distance(int x0, int y0, int x1, int y1);
72     void buildSCDMatrix(int r);
73 
74     const SplashScreenParams *screenParams; // params to create the other members
75     unsigned char *mat; // threshold matrix
76     int size; // size of the threshold matrix
77     int sizeM1; // size - 1
78     int log2Size; // log2(size)
79     unsigned char minVal; // any pixel value below minVal generates
80                           //   solid black
81     unsigned char maxVal; // any pixel value above maxVal generates
82                           //   solid white
83 };
84 
85 #endif
86