1
2//----------------------------------------------------------------------------
3// XYQ: 2006-01-22 Copied from AGG project.
4// This file uses only integer data, so it's suitable for all platforms.
5//----------------------------------------------------------------------------
6//----------------------------------------------------------------------------
7// Anti-Grain Geometry - Version 2.3
8// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
9//
10// Permission to copy, use, modify, sell and distribute this software
11// is granted provided this copyright notice appears in all copies.
12// This software is provided "as is" without express or implied
13// warranty, and with no claim as to its suitability for any purpose.
14//
15//----------------------------------------------------------------------------
16//
17// The author gratefully acknowleges the support of David Turner,
18// Robert Wilhelm, and Werner Lemberg - the authors of the FreeType
19// libray - in producing this work. See http://www.freetype.org for details.
20//
21//----------------------------------------------------------------------------
22// Contact: mcseem@antigrain.com
23//          mcseemagg@yahoo.com
24//          http://www.antigrain.com
25//----------------------------------------------------------------------------
26//
27// Adaptation for 32-bit screen coordinates has been sponsored by
28// Liberty Technology Systems, Inc., visit http://lib-sys.com
29//
30// Liberty Technology Systems, Inc. is the provider of
31// PostScript and PDF technology for software developers.
32//
33//----------------------------------------------------------------------------
34//
35// Class outline_aa - implementation.
36//
37// Initially the rendering algorithm was designed by David Turner and the
38// other authors of the FreeType library - see the above notice. I nearly
39// created a similar renderer, but still I was far from David's work.
40// I completely redesigned the original code and adapted it for Anti-Grain
41// ideas. Two functions - render_line and render_hline are the core of
42// the algorithm - they calculate the exact coverage of each pixel cell
43// of the polygon. I left these functions almost as is, because there's
44// no way to improve the perfection - hats off to David and his group!
45//
46// All other code is very different from the original.
47//
48//----------------------------------------------------------------------------
49#include "../../../../include/fxcrt/fx_ext.h"
50#include <limits.h>
51#include "agg_rasterizer_scanline_aa.h"
52namespace agg
53{
54AGG_INLINE void cell_aa::set_cover(int c, int a)
55{
56    cover = c;
57    area = a;
58}
59AGG_INLINE void cell_aa::add_cover(int c, int a)
60{
61    cover += c;
62    area += a;
63}
64AGG_INLINE void cell_aa::set_coord(int cx, int cy)
65{
66    x = cx;
67    y = cy;
68}
69AGG_INLINE void cell_aa::set(int cx, int cy, int c, int a)
70{
71    x = cx;
72    y = cy;
73    cover = c;
74    area = a;
75}
76outline_aa::~outline_aa()
77{
78    if(m_num_blocks) {
79        cell_aa** ptr = m_cells + m_num_blocks - 1;
80        while(m_num_blocks--) {
81            FX_Free(*ptr);
82            ptr--;
83        }
84        FX_Free(m_cells);
85    }
86}
87outline_aa::outline_aa() :
88    m_num_blocks(0),
89    m_max_blocks(0),
90    m_cur_block(0),
91    m_num_cells(0),
92    m_cells(0),
93    m_cur_cell_ptr(0),
94    m_cur_x(0),
95    m_cur_y(0),
96    m_min_x(0x7FFFFFFF),
97    m_min_y(0x7FFFFFFF),
98    m_max_x(-0x7FFFFFFF),
99    m_max_y(-0x7FFFFFFF),
100    m_sorted(false)
101{
102    m_cur_cell.set(0x7FFF, 0x7FFF, 0, 0);
103}
104void outline_aa::reset()
105{
106    m_num_cells = 0;
107    m_cur_block = 0;
108    m_cur_cell.set(0x7FFF, 0x7FFF, 0, 0);
109    m_sorted = false;
110    m_min_x =  0x7FFFFFFF;
111    m_min_y =  0x7FFFFFFF;
112    m_max_x = -0x7FFFFFFF;
113    m_max_y = -0x7FFFFFFF;
114}
115void outline_aa::allocate_block()
116{
117    if(m_cur_block >= m_num_blocks) {
118        if(m_num_blocks >= m_max_blocks) {
119            cell_aa** new_cells = FX_Alloc( cell_aa*, m_max_blocks + cell_block_pool);
120            if (!new_cells) {
121                return;
122            }
123            if(m_cells) {
124                FXSYS_memcpy32(new_cells, m_cells, m_max_blocks * sizeof(cell_aa*));
125                FX_Free(m_cells);
126            }
127            m_cells = new_cells;
128            m_max_blocks += cell_block_pool;
129        }
130        m_cells[m_num_blocks++] = FX_Alloc(cell_aa, cell_block_size);
131        if (!m_cells[m_num_blocks - 1]) {
132            return;
133        }
134    }
135    m_cur_cell_ptr = m_cells[m_cur_block++];
136}
137AGG_INLINE void outline_aa::add_cur_cell()
138{
139    if(m_cur_cell.area | m_cur_cell.cover) {
140        if((m_num_cells & cell_block_mask) == 0) {
141            if(m_num_blocks >= cell_block_limit) {
142                return;
143            }
144            allocate_block();
145        }
146        *m_cur_cell_ptr++ = m_cur_cell;
147        ++m_num_cells;
148    }
149}
150AGG_INLINE void outline_aa::set_cur_cell(int x, int y)
151{
152    if(m_cur_cell.x != x || m_cur_cell.y != y) {
153        add_cur_cell();
154        m_cur_cell.set(x, y, 0, 0);
155        if(x < m_min_x) {
156            m_min_x = x;
157        }
158        if(x > m_max_x) {
159            m_max_x = x;
160        }
161        if(y < m_min_y) {
162            m_min_y = y;
163        }
164        if(y > m_max_y) {
165            m_max_y = y;
166        }
167    }
168}
169AGG_INLINE void outline_aa::render_hline(int ey, int x1, int y1, int x2, int y2)
170{
171    int ex1 = x1 >> poly_base_shift;
172    int ex2 = x2 >> poly_base_shift;
173    int fx1 = x1 & poly_base_mask;
174    int fx2 = x2 & poly_base_mask;
175    int delta, p, first, dx;
176    int incr, lift, mod, rem;
177    if(y1 == y2) {
178        set_cur_cell(ex2, ey);
179        return;
180    }
181    if(ex1 == ex2) {
182        delta = y2 - y1;
183        m_cur_cell.add_cover(delta, (fx1 + fx2) * delta);
184        return;
185    }
186    p     = (poly_base_size - fx1) * (y2 - y1);
187    first = poly_base_size;
188    incr  = 1;
189    dx = x2 - x1;
190    if(dx < 0) {
191        p     = fx1 * (y2 - y1);
192        first = 0;
193        incr  = -1;
194        dx    = -dx;
195    }
196    delta = p / dx;
197    mod   = p % dx;
198    if(mod < 0) {
199        delta--;
200        mod += dx;
201    }
202    m_cur_cell.add_cover(delta, (fx1 + first) * delta);
203    ex1 += incr;
204    set_cur_cell(ex1, ey);
205    y1  += delta;
206    if(ex1 != ex2) {
207        p     = poly_base_size * (y2 - y1 + delta);
208        lift  = p / dx;
209        rem   = p % dx;
210        if (rem < 0) {
211            lift--;
212            rem += dx;
213        }
214        mod -= dx;
215        while (ex1 != ex2) {
216            delta = lift;
217            mod  += rem;
218            if(mod >= 0) {
219                mod -= dx;
220                delta++;
221            }
222            m_cur_cell.add_cover(delta, (poly_base_size) * delta);
223            y1  += delta;
224            ex1 += incr;
225            set_cur_cell(ex1, ey);
226        }
227    }
228    delta = y2 - y1;
229    m_cur_cell.add_cover(delta, (fx2 + poly_base_size - first) * delta);
230}
231void outline_aa::render_line(int x1, int y1, int x2, int y2)
232{
233    enum dx_limit_e { dx_limit = 16384 << poly_base_shift };
234    int dx = x2 - x1;
235    if(dx >= dx_limit || dx <= -dx_limit) {
236        int cx = (x1 + x2) >> 1;
237        int cy = (y1 + y2) >> 1;
238        render_line(x1, y1, cx, cy);
239        render_line(cx, cy, x2, y2);
240    }
241    int dy = y2 - y1;
242    int ey1 = y1 >> poly_base_shift;
243    int ey2 = y2 >> poly_base_shift;
244    int fy1 = y1 & poly_base_mask;
245    int fy2 = y2 & poly_base_mask;
246    int x_from, x_to;
247    int p, rem, mod, lift, delta, first, incr;
248    if(ey1 == ey2) {
249        render_hline(ey1, x1, fy1, x2, fy2);
250        return;
251    }
252    incr  = 1;
253    if(dx == 0) {
254        int ex = x1 >> poly_base_shift;
255        int two_fx = (x1 - (ex << poly_base_shift)) << 1;
256        int area;
257        first = poly_base_size;
258        if(dy < 0) {
259            first = 0;
260            incr  = -1;
261        }
262        x_from = x1;
263        delta = first - fy1;
264        m_cur_cell.add_cover(delta, two_fx * delta);
265        ey1 += incr;
266        set_cur_cell(ex, ey1);
267        delta = first + first - poly_base_size;
268        area = two_fx * delta;
269        while(ey1 != ey2) {
270            m_cur_cell.set_cover(delta, area);
271            ey1 += incr;
272            set_cur_cell(ex, ey1);
273        }
274        delta = fy2 - poly_base_size + first;
275        m_cur_cell.add_cover(delta, two_fx * delta);
276        return;
277    }
278    p     = (poly_base_size - fy1) * dx;
279    first = poly_base_size;
280    if(dy < 0) {
281        p     = fy1 * dx;
282        first = 0;
283        incr  = -1;
284        dy    = -dy;
285    }
286    delta = p / dy;
287    mod   = p % dy;
288    if(mod < 0) {
289        delta--;
290        mod += dy;
291    }
292    x_from = x1 + delta;
293    render_hline(ey1, x1, fy1, x_from, first);
294    ey1 += incr;
295    set_cur_cell(x_from >> poly_base_shift, ey1);
296    if(ey1 != ey2) {
297        p     = poly_base_size * dx;
298        lift  = p / dy;
299        rem   = p % dy;
300        if(rem < 0) {
301            lift--;
302            rem += dy;
303        }
304        mod -= dy;
305        while(ey1 != ey2) {
306            delta = lift;
307            mod  += rem;
308            if (mod >= 0) {
309                mod -= dy;
310                delta++;
311            }
312            x_to = x_from + delta;
313            render_hline(ey1, x_from, poly_base_size - first, x_to, first);
314            x_from = x_to;
315            ey1 += incr;
316            set_cur_cell(x_from >> poly_base_shift, ey1);
317        }
318    }
319    render_hline(ey1, x_from, poly_base_size - first, x2, fy2);
320}
321void outline_aa::move_to(int x, int y)
322{
323    if(m_sorted) {
324        reset();
325    }
326    set_cur_cell(x >> poly_base_shift, y >> poly_base_shift);
327    m_cur_x = x;
328    m_cur_y = y;
329}
330void outline_aa::line_to(int x, int y)
331{
332    render_line(m_cur_x, m_cur_y, x, y);
333    m_cur_x = x;
334    m_cur_y = y;
335    m_sorted = false;
336}
337template <class T> static AGG_INLINE void swap_cells(T* a, T* b)
338{
339    T temp = *a;
340    *a = *b;
341    *b = temp;
342}
343enum {
344    qsort_threshold = 9
345};
346static void qsort_cells(cell_aa** start, unsigned num)
347{
348    cell_aa**  stack[80];
349    cell_aa*** top;
350    cell_aa**  limit;
351    cell_aa**  base;
352    limit = start + num;
353    base  = start;
354    top   = stack;
355    for (;;) {
356        int len = int(limit - base);
357        cell_aa** i;
358        cell_aa** j;
359        cell_aa** pivot;
360        if(len > qsort_threshold) {
361            pivot = base + len / 2;
362            swap_cells(base, pivot);
363            i = base + 1;
364            j = limit - 1;
365            if((*j)->x < (*i)->x) {
366                swap_cells(i, j);
367            }
368            if((*base)->x < (*i)->x) {
369                swap_cells(base, i);
370            }
371            if((*j)->x < (*base)->x) {
372                swap_cells(base, j);
373            }
374            for(;;) {
375                int x = (*base)->x;
376                do {
377                    i++;
378                } while( (*i)->x < x );
379                do {
380                    j--;
381                } while( x < (*j)->x );
382                if(i > j) {
383                    break;
384                }
385                swap_cells(i, j);
386            }
387            swap_cells(base, j);
388            if(j - base > limit - i) {
389                top[0] = base;
390                top[1] = j;
391                base   = i;
392            } else {
393                top[0] = i;
394                top[1] = limit;
395                limit  = j;
396            }
397            top += 2;
398        } else {
399            j = base;
400            i = j + 1;
401            for(; i < limit; j = i, i++) {
402                for(; j[1]->x < (*j)->x; j--) {
403                    swap_cells(j + 1, j);
404                    if (j == base) {
405                        break;
406                    }
407                }
408            }
409            if(top > stack) {
410                top  -= 2;
411                base  = top[0];
412                limit = top[1];
413            } else {
414                break;
415            }
416        }
417    }
418}
419void outline_aa::sort_cells()
420{
421    if(m_sorted) {
422        return;
423    }
424    add_cur_cell();
425    if(m_num_cells == 0) {
426        return;
427    }
428    m_sorted_cells.allocate(m_num_cells, 16);
429    if (m_max_y > 0 && m_min_y < 0 && -m_min_y > INT_MAX - m_max_y) {
430        return;
431    }
432    unsigned size = m_max_y - m_min_y;
433    if (size + 1 < size) {
434        return;
435    }
436    size++;
437    m_sorted_y.allocate(size, 16);
438    m_sorted_y.zero();
439    cell_aa** block_ptr = m_cells;
440    cell_aa*  cell_ptr = NULL;
441    unsigned nb = m_num_cells >> cell_block_shift;
442    unsigned i;
443    while(nb--) {
444        cell_ptr = *block_ptr++;
445        i = cell_block_size;
446        while(i--) {
447            m_sorted_y[cell_ptr->y - m_min_y].start++;
448            ++cell_ptr;
449        }
450    }
451    i = m_num_cells & cell_block_mask;
452    if (i) {
453        cell_ptr = *block_ptr++;
454    }
455    while(i--) {
456        m_sorted_y[cell_ptr->y - m_min_y].start++;
457        ++cell_ptr;
458    }
459    unsigned start = 0;
460    for(i = 0; i < m_sorted_y.size(); i++) {
461        unsigned v = m_sorted_y[i].start;
462        m_sorted_y[i].start = start;
463        start += v;
464    }
465    block_ptr = m_cells;
466    nb = m_num_cells >> cell_block_shift;
467    while(nb--) {
468        cell_ptr = *block_ptr++;
469        i = cell_block_size;
470        while(i--) {
471            sorted_y& cur_y = m_sorted_y[cell_ptr->y - m_min_y];
472            m_sorted_cells[cur_y.start + cur_y.num] = cell_ptr;
473            ++cur_y.num;
474            ++cell_ptr;
475        }
476    }
477    i = m_num_cells & cell_block_mask;
478    if (i) {
479        cell_ptr = *block_ptr++;
480    }
481    while(i--) {
482        sorted_y& cur_y = m_sorted_y[cell_ptr->y - m_min_y];
483        m_sorted_cells[cur_y.start + cur_y.num] = cell_ptr;
484        ++cur_y.num;
485        ++cell_ptr;
486    }
487    for(i = 0; i < m_sorted_y.size(); i++) {
488        const sorted_y& cur_y = m_sorted_y[i];
489        if(cur_y.num) {
490            qsort_cells(m_sorted_cells.data() + cur_y.start, cur_y.num);
491        }
492    }
493    m_sorted = true;
494}
495}
496