Improve lbx_colour structure layout.

[liblbx.git] / src / pnm.c

diff --git a/src/pnm.c b/src/pnm.c
index 1596c5a1e85114bfc12e631f429ea2ef46bbbb7e..43108f8e32a7ec3cfc2dbe0a8cb1c090bc0bbe52 100644 (file)
--- a/src/pnm.c
+++ b/src/pnm.c
@@ -20,6 +20,7 @@
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <stdbool.h>
 #include <stdarg.h>
 #include <assert.h>
@@ -311,6 +312,68 @@ err:
        return -1;
 }
 
+static void pam_format_rgba(unsigned char *rowbuf, const unsigned char *pixels,
+                            unsigned char *mask, unsigned width,
+                            unsigned long offset, struct lbx_colour *palette)
+{
+       unsigned x;
+
+       for (x = 0; x < width; x++) {
+               struct lbx_colour val = palette[pixels[offset+x]];
+               unsigned vis = 1 & ( mask[(offset+x)/CHAR_BIT]
+                                     >> ((offset+x)%CHAR_BIT) );
+
+               if (sizeof val == 4) {
+                       memcpy(rowbuf+4ul*x, &val, 4);
+               } else {
+                       rowbuf[4ul*x+0] = val.red;
+                       rowbuf[4ul*x+1] = val.green;
+                       rowbuf[4ul*x+2] = val.blue;
+               }
+               rowbuf[4ul*x+3] = -vis & 0x3f;
+       }
+}
+
+static void pam_format_rgb(unsigned char *rowbuf, const unsigned char *pixels,
+                           unsigned width, unsigned long offset,
+                           struct lbx_colour *palette)
+{
+       unsigned x;
+
+       for (x = 0; x < width; x++) {
+               struct lbx_colour val = palette[pixels[offset+x]];
+
+               if (sizeof val == 4) {
+                       memcpy(rowbuf+3ul*x, &val, 4);
+               } else {
+                       rowbuf[3ul*x+0] = val.red;
+                       rowbuf[3ul*x+1] = val.green;
+                       rowbuf[3ul*x+2] = val.blue;
+               }
+       }
+}
+
+static void pam_format_ga(unsigned char *rowbuf,
+                          const unsigned char *pixels, const unsigned char *mask,
+                          unsigned width, unsigned long offset)
+{
+       unsigned x;
+
+       for (x = 0; x < width; x++) {
+               unsigned vis = 1 & ( mask[(offset+x)/CHAR_BIT]
+                                     >> ((offset+x)%CHAR_BIT) );
+
+               rowbuf[2ul*x+0] = pixels[offset+x];
+               rowbuf[2ul*x+1] = -vis & 0xff;
+       }
+}
+
+static void pam_format_g(unsigned char *rowbuf, const unsigned char *pixels,
+                         unsigned width, unsigned long offset)
+{
+       memcpy(rowbuf, pixels+offset, width);
+}
+
 /*
  * Output filter for Netpbm's PAM format.  This format combines the features
  * of all the other Netpbm formats, supporting RGB and grayscale images with
@@ -322,12 +385,18 @@ int img_output_pam(FILE *f, const char *filename,
                    struct lbx_colour *palette)
 {
        bool masked = img_is_masked(mask, width, height);
-       unsigned x, y, depth, maxval = palette ? 63 : 255;
        unsigned char *rowbuf;
+       unsigned long offset;
+       unsigned y, depth;
        int rc;
 
        depth = (palette ? 3 : 1) + masked;
-       if (width > (size_t)-1 / depth || !(rowbuf = malloc(width * depth))) {
+       if (width >= (size_t)-1 / depth)
+               goto alloc_err;
+
+       rowbuf = malloc(width * depth + 1);
+       if (!rowbuf) {
+alloc_err:
                tool_err(-1, "failed to allocate memory");
                return -1;
        }
@@ -337,8 +406,9 @@ int img_output_pam(FILE *f, const char *filename,
        if (rc < 0)
                goto write_err;
 
-       rc = fprintf_ascii(f, "MAXVAL %u\nTUPLTYPE %s",
-                             maxval, palette ? "RGB" : "GRAYSCALE");
+       rc = fprintf_ascii(f, "MAXVAL %d\nTUPLTYPE %s",
+                             palette ? 63 : 255,
+                             palette ? "RGB" : "GRAYSCALE");
        if (rc < 0)
                goto write_err;
 
@@ -346,26 +416,20 @@ int img_output_pam(FILE *f, const char *filename,
        if (rc < 0)
                goto write_err;
 
-       for (y = 0; y < height; y++) {
-               for (x = 0; x < width; x++) {
-                       unsigned long offset = (unsigned long) y * width + x;
-                       size_t p = (size_t)depth * x; // pixel start
-
-                       if (palette) {
-                               struct lbx_colour *c = &palette[pixels[offset]];
-                               rowbuf[p+0] = c->red;
-                               rowbuf[p+1] = c->green;
-                               rowbuf[p+2] = c->blue;
-                       } else {
-                               rowbuf[p+0] = pixels[offset];
-                       }
-
-                       if (masked) {
-                               bool vis = 1 & ( mask[offset/CHAR_BIT]
-                                                >> (offset%CHAR_BIT) );
-
-                               rowbuf[p+depth-1] = vis*maxval;
-                       }
+       for (offset = y = 0; y < height; y++, offset += width) {
+               switch (depth) {
+               case 4:
+                       pam_format_rgba(rowbuf, pixels, mask, width, offset, palette);
+                       break;
+               case 3:
+                       pam_format_rgb(rowbuf, pixels, width, offset, palette);
+                       break;
+               case 2:
+                       pam_format_ga(rowbuf, pixels, mask, width, offset);
+                       break;
+               case 1:
+                       pam_format_g(rowbuf, pixels, width, offset);
+                       break;
                }
 
                if (fwrite(rowbuf, depth, width, f) < width)
@@ -376,7 +440,6 @@ int img_output_pam(FILE *f, const char *filename,
        return 0;
 write_err:
        tool_err(0, "error writing %s", filename);
-
        free(rowbuf);
        return -1;
 }