source/texk/web2c/luatexdir/pdf/pdfsetmatrix.w

   1 % pdfsetmatrix.w
   2 %
   3 % Copyright 2009 Taco Hoekwater <taco@@luatex.org>
   4 %
   5 % This file is part of LuaTeX.
   6 %
   7 % LuaTeX is free software; you can redistribute it and/or modify it under
   8 % the terms of the GNU General Public License as published by the Free
   9 % Software Foundation; either version 2 of the License, or (at your
  10 % option) any later version.
  11 %
  12 % LuaTeX is distributed in the hope that it will be useful, but WITHOUT
  13 % ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 % FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  15 % License for more details.
  16 %
  17 % You should have received a copy of the GNU General Public License along
  18 % with LuaTeX; if not, see <http://www.gnu.org/licenses/>.
  19
  20 @ @c
  21
  22 #include "ptexlib.h"
  23
  24 @ stack for \.{\\pdfextension setmatrix}
  25
  26 @c
  27 matrix_entry *matrix_stack = NULL;
  28 int matrix_stack_size = 0;
  29 int matrix_stack_used = 0;
  30
  31 @ @c
  32 boolean matrixused(void)
  33 {
  34     return matrix_stack_used > 0;
  35 }
  36
  37 static void matrix_stack_room(void)
  38 {
  39     matrix_entry *new_stack;
  40     if (matrix_stack_used >= matrix_stack_size) {
  41         matrix_stack_size += STACK_INCREMENT;
  42         new_stack = xtalloc((unsigned) matrix_stack_size, matrix_entry);
  43         memcpy((void *) new_stack, (void *) matrix_stack, (unsigned) matrix_stack_used * sizeof(matrix_entry));
  44         xfree(matrix_stack);
  45         matrix_stack = new_stack;
  46     }
  47 }
  48
  49 @ \.{\\pdfextension setmatrix{a b c d}}
  50
  51 |e| := pos.h
  52
  53 |f| := pos.v
  54
  55 |M_top|: current active matrix at the top of the matrix stack
  56
  57 The origin of \.{\\pdfextension setmatrix} is the current point. The annotation
  58 coordinate system is the original page coordinate system. When pdfTeX calculates
  59 annotation rectangles it does not take into account this transformations, it uses
  60 the original coordinate system. To get the corrected values, first we go back to
  61 the origin, perform the transformation and go back:
  62
  63 {\obeylines\obeyspaces\tt
  64     (  1   0  0 )   ( a b 0 )   ( 1 0 0 )
  65     (  0   1  0 ) x ( c d 0 ) x ( 0 1 0 ) x M\_top
  66     ( -e  -f  1 )   ( 0 0 1 )   ( e f 1 )
  67
  68     ( 1  0  0 )   (  a  b 0 )
  69   = ( 0  1  0 ) x (  c  d 0 ) x M\_top
  70     ( e  f  1 )   ( -e -f 1 )
  71
  72     ( a         b         0 )
  73   = ( c         d         0 ) x M\_top
  74     ( e(1-a)-fc f(1-d)-eb 1 )
  75 }
  76
  77 @c
  78 static void pdfsetmatrix(const char *in, scaledpos pos)
  79 {
  80     /*
  81         Argument of \.{\\pdfextension setmatrix} starts with |str_pool[in]| and ends
  82         before |str_pool[pool_ptr]|.
  83     */
  84     matrix_entry x, *y, *z;
  85     if (global_shipping_mode == SHIPPING_PAGE) {
  86         if (sscanf((const char *) in, " %lf %lf %lf %lf ", &x.a, &x.b, &x.c, &x.d) != 4) {
  87             formatted_warning("pdf backend","unrecognized format of setmatrix: %s", in);
  88             return;
  89         }
  90         /* calculate this transformation matrix */
  91         x.e = (double) pos.h * (1.0 - x.a) - (double) pos.v * x.c;
  92         x.f = (double) pos.v * (1.0 - x.d) - (double) pos.h * x.b;
  93         matrix_stack_room();
  94         z = &matrix_stack[matrix_stack_used];
  95         if (matrix_stack_used > 0) {
  96             y = &matrix_stack[matrix_stack_used - 1];
  97             z->a = x.a * y->a + x.b * y->c;
  98             z->b = x.a * y->b + x.b * y->d;
  99             z->c = x.c * y->a + x.d * y->c;
 100             z->d = x.c * y->b + x.d * y->d;
 101             z->e = x.e * y->a + x.f * y->c + y->e;
 102             z->f = x.e * y->b + x.f * y->d + y->f;
 103         } else {
 104             z->a = x.a;
 105             z->b = x.b;
 106             z->c = x.c;
 107             z->d = x.d;
 108             z->e = x.e;
 109             z->f = x.f;
 110         }
 111         matrix_stack_used++;
 112     }
 113 }
 114
 115 @ Apply matrix to point (x,y)
 116
 117 {\obeylines\obeyspaces\tt
 118                ( a b 0 )
 119    ( x y 1 ) x ( c d 0 ) = ( xa+yc+e xb+yd+f 1 )
 120                ( e f 1 )
 121 }
 122
 123 If \.{\\pdfextension setmatrix} wasn't used, then return the value unchanged.
 124
 125 @ Return values for matrix tranform functions:
 126
 127 @c
 128 static scaled ret_llx;
 129 static scaled ret_lly;
 130 static scaled ret_urx;
 131 static scaled ret_ury;
 132
 133 scaled getllx(void)
 134 {
 135     return ret_llx;
 136 }
 137
 138 scaled getlly(void)
 139 {
 140     return ret_lly;
 141 }
 142
 143 scaled geturx(void)
 144 {
 145     return ret_urx;
 146 }
 147
 148 scaled getury(void)
 149 {
 150     return ret_ury;
 151 }
 152
 153 @ @c
 154 static int last_llx;
 155 static int last_lly;
 156 static int last_urx;
 157 static int last_ury;
 158
 159 #define DO_ROUND(x)  ((x > 0) ? (x + .5) : (x - .5))
 160 #define DO_MIN(a, b) ((a < b) ? a : b)
 161 #define DO_MAX(a, b) ((a > b) ? a : b)
 162
 163 static void do_matrixtransform(scaled x, scaled y, scaled * retx, scaled * rety)
 164 {
 165     matrix_entry *m = &matrix_stack[matrix_stack_used - 1];
 166     double x_old = x;
 167     double y_old = y;
 168     double x_new = x_old * m->a + y_old * m->c + m->e;
 169     double y_new = x_old * m->b + y_old * m->d + m->f;
 170     *retx = (scaled) DO_ROUND(x_new);
 171     *rety = (scaled) DO_ROUND(y_new);
 172 }
 173
 174 void matrixtransformrect(scaled llx, scaled lly, scaled urx, scaled ury)
 175 {
 176     scaled x1, x2, x3, x4, y1, y2, y3, y4;
 177     if (global_shipping_mode == SHIPPING_PAGE && matrix_stack_used > 0) {
 178         last_llx = llx;
 179         last_lly = lly;
 180         last_urx = urx;
 181         last_ury = ury;
 182         do_matrixtransform(llx, lly, &x1, &y1);
 183         do_matrixtransform(llx, ury, &x2, &y2);
 184         do_matrixtransform(urx, lly, &x3, &y3);
 185         do_matrixtransform(urx, ury, &x4, &y4);
 186         ret_llx = DO_MIN(DO_MIN(x1, x2), DO_MIN(x3, x4));
 187         ret_lly = DO_MIN(DO_MIN(y1, y2), DO_MIN(y3, y4));
 188         ret_urx = DO_MAX(DO_MAX(x1, x2), DO_MAX(x3, x4));
 189         ret_ury = DO_MAX(DO_MAX(y1, y2), DO_MAX(y3, y4));
 190     } else {
 191         ret_llx = llx;
 192         ret_lly = lly;
 193         ret_urx = urx;
 194         ret_ury = ury;
 195     }
 196 }
 197
 198 void matrixtransformpoint(scaled x, scaled y)
 199 {
 200     if (global_shipping_mode == SHIPPING_PAGE && matrix_stack_used > 0) {
 201         do_matrixtransform(x, y, &ret_llx, &ret_lly);
 202     } else {
 203         ret_llx = x;
 204         ret_lly = y;
 205     }
 206 }
 207
 208 void matrixrecalculate(scaled urx)
 209 {
 210     matrixtransformrect(last_llx, last_lly, urx, last_ury);
 211 }
 212
 213 @ @c
 214 void pdf_out_setmatrix(PDF pdf, halfword p)
 215 {
 216     scaledpos pos = pdf->posstruct->pos;
 217     int old_setting;            /* holds print |selector| */
 218     str_number s;
 219     old_setting = selector;
 220     selector = new_string;
 221     show_token_list(token_link(pdf_setmatrix_data(p)), null, -1);
 222     pdfsetmatrix((char *) cur_string, pos);
 223     tprint(" 0 0 cm");
 224     selector = old_setting;
 225     s = make_string();
 226     pdf_literal(pdf, s, set_origin, false);
 227     flush_str(s);
 228 }