GRASS GIS 7 Programmer's Manual  7.5.svn(2017)-r71933
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cairodriver/raster.c
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1 /*!
2  \file lib/cairodriver/raster.c
3 
4  \brief GRASS cairo display driver - draw raster
5 
6  (C) 2007-2014 by Lars Ahlzen and the GRASS Development Team
7 
8  This program is free software under the GNU General Public License
9  (>=v2). Read the file COPYING that comes with GRASS for details.
10 
11  \author Lars Ahlzen <lars ahlzen.com> (original contibutor)
12  \author Glynn Clements
13 */
14 
15 #include <math.h>
16 
17 #include "cairodriver.h"
18 #include <grass/glocale.h>
19 
20 #define MAX_IMAGE_SIZE 32767
21 #ifndef MIN
22 #define MIN(a,b) ((a)<(b)?(a):(b))
23 #endif
24 #ifndef MAX
25 #define MAX(a,b) ((a)>(b)?(a):(b))
26 #endif
27 
28 static int src_t, src_b, src_l, src_r, src_w, src_h;
29 static int dst_t, dst_b, dst_l, dst_r, dst_w, dst_h;
30 
31 static int *trans;
32 
33 static cairo_surface_t *src_surf;
34 static unsigned char *src_data;
35 static int src_stride, ca_row;
36 
37 static int masked;
38 
39 static double scale(double k, int src_0, int src_1, int dst_0, int dst_1)
40 {
41  return dst_0 + (double) (k - src_0) * (dst_1 - dst_0) / (src_1 - src_0);
42 }
43 
44 static int scale_fwd_y(int sy)
45 {
46  return (int)floor(scale(sy, src_t, src_b, dst_t, dst_b) + 0.5);
47 }
48 
49 static int scale_rev_x(int dx)
50 {
51  return (int)floor(scale(dx + 0.5, dst_l, dst_r, src_l, src_r));
52 }
53 
54 static int next_row(int sy, int dy)
55 {
56  sy++;
57 
58  for (;;) {
59  int y = scale_fwd_y(sy);
60 
61  if (y > dy)
62  return sy - 1;
63  sy++;
64  }
65 }
66 
67 /*!
68  \brief Start drawing raster
69 
70  \todo are top and left swapped?
71 
72  \param mask non-zero int for mask
73  \param s source (map) extent (left, right, top, bottom)
74  \param d destination (image) extent (left, right, top, bottom)
75 */
76 void Cairo_begin_raster(int mask, int s[2][2], double d[2][2])
77 {
78  int i;
79  cairo_status_t status;
80 
81  masked = mask;
82 
83  src_l = s[0][0];
84  src_r = s[0][1];
85  src_t = s[1][0];
86  src_b = s[1][1];
87 
88  src_w = src_r - src_l;
89  src_h = src_b - src_t;
90 
91  dst_l = (int) floor(d[0][0] + 0.5);
92  dst_r = (int) floor(d[0][1] + 0.5);
93  dst_t = (int) floor(d[1][0] + 0.5);
94  dst_b = (int) floor(d[1][1] + 0.5);
95 
96  dst_w = dst_r - dst_l;
97  dst_h = dst_b - dst_t;
98 
99  G_debug(1, "Cairo_begin_raster(): masked=%d, src_lrtb=%d %d %d %d -> w/h=%d %d, "
100  "dst_lrtb=%d %d %d %d -> w/h=%d %d",
101  masked, src_l, src_r, src_t, src_b, src_w, src_h,
102  dst_l, dst_r, dst_t, dst_b, dst_w, dst_h);
103 
104  /* create source surface */
105  src_surf = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, ca.width, ca.height);
106  status = cairo_surface_status(src_surf);
107  if (status != CAIRO_STATUS_SUCCESS)
108  G_fatal_error("%s - %s - size: %dx%d (cairo limit: %dx%d)",
109  _("Failed to create cairo surface"),
110  cairo_status_to_string (status), ca.width, ca.height,
112 
113  src_data = cairo_image_surface_get_data(src_surf);
114  src_stride = cairo_image_surface_get_stride(src_surf);
115  ca_row = 0;
116 
117  /* allocate buffer for down-sampling data */
118  trans = G_malloc(dst_w * sizeof(int));
119  for (i = 0; i < dst_w; i++)
120  trans[i] = scale_rev_x(dst_l + i);
121 }
122 
123 /*!
124  \brief Draw raster row
125 
126  \param n number of cells
127  \param row raster row (starting at 0)
128  \param red,grn,blu,nul red,green,blue and null value
129 
130  \return next row
131 */
132 int Cairo_raster(int n, int row,
133  const unsigned char *red, const unsigned char *grn,
134  const unsigned char *blu, const unsigned char *nul)
135 {
136  int d_y0 = scale_fwd_y(row + 0);
137  int d_y1 = scale_fwd_y(row + 1);
138  int d_rows = d_y1 - d_y0;
139  int x0 = MAX(0 - dst_l, 0);
140  int x1 = MIN(ca.width - dst_l, dst_w);
141  int y0 = MAX(0 - d_y0, 0);
142  int y1 = MIN(ca.height - d_y0, d_rows);
143  int x, y;
144 
145  if (y1 <= y0)
146  return next_row(row, d_y1);
147 
148  G_debug(3, "Cairo_raster(): n=%d row=%d", n, row);
149 
150  for (x = x0; x < x1; x++) {
151  int xx = dst_l + x;
152  int j = trans[x];
153  unsigned int c;
154 
155  if (masked && nul && nul[j])
156  c = 0;
157  else {
158  unsigned int r = red[j];
159  unsigned int g = grn[j];
160  unsigned int b = blu[j];
161  unsigned int a = 0xFF;
162  c = (a << 24) + (r << 16) + (g << 8) + (b << 0);
163  }
164 
165  for (y = y0; y < y1; y++) {
166  int yy = d_y0 + y;
167  *(unsigned int *)(src_data + yy * src_stride + xx * 4) = c;
168  }
169  }
170 
171  ca.modified = 1;
172  ca_row++;
173 
174  return next_row(row, d_y1);
175 }
176 
177 /*!
178  \brief Finish drawing raster
179 */
181 {
182  G_debug(1, "Cairo_end_raster()");
183 
184  /* paint source surface onto destination (scaled) */
185  cairo_save(cairo);
186  /* cairo_translate(cairo, dst_l, dst_t); */
187  /* cairo_scale(cairo, dst_w / src_w, dst_h / src_h); */
188  cairo_surface_mark_dirty(src_surf);
189  cairo_set_source_surface(cairo, src_surf, 0, 0);
190  cairo_pattern_set_filter(cairo_get_source(cairo), CAIRO_FILTER_NEAREST);
191  cairo_paint(cairo);
192  cairo_restore(cairo);
193 
194  /* cleanup */
195  G_free(trans);
196  cairo_surface_destroy(src_surf);
197  ca.modified = 1;
198 }
void G_free(void *buf)
Free allocated memory.
Definition: gis/alloc.c:149
void Cairo_begin_raster(int, int[2][2], double[2][2])
Start drawing raster.
struct cairo_state ca
#define x
#define MAX_IMAGE_SIZE
void G_fatal_error(const char *msg,...)
Print a fatal error message to stderr.
Definition: gis/error.c:159
double b
Definition: r_raster.c:39
cairo_t * cairo
int G_debug(int level, const char *msg,...)
Print debugging message.
Definition: debug.c:65
float g
Definition: named_colr.c:8
int Cairo_raster(int, int, const unsigned char *, const unsigned char *, const unsigned char *, const unsigned char *)
Draw raster row.
GRASS cairo display driver - header file.
#define MAX(a, b)
#define _(str)
Definition: glocale.h:13
void Cairo_end_raster(void)
Finish drawing raster.
int
Reads the categories file for map name in mapset and stores the categories in the pcats structure...
#define MIN(a, b)
double r
Definition: r_raster.c:39