Changeset 3531

Timestamp:

05/27/09 07:04:41 (4 years ago)

Author:

sam

Message:

img2twit: store w+1,h+1 instead of w,h since neither width nor height can
be zero.

File:

• libpipi/trunk/examples/img2twit.cpp (modified) (8 diffs)

libpipi/trunk/examples/img2twit.cpp

@@ -63 +63 @@
 
 /* The maximum image size we want to support */
-#define MAX_W 4000
-#define MAX_H 4000
+#define RANGE_W 4000
+#define RANGE_H 4000
 
 /* How does the algorithm work: one point per cell, or two */
@@ -443 +443 @@
 }
 
+static inline void index2cell(int index, int *dx, int *dy)
+{
+    // This check will be used once we add points to our list
+    //if(index < dw * dh * POINTS_PER_CELL)
+    {
+        *dx = (index / POINTS_PER_CELL) % dw;
+        *dy = (index / POINTS_PER_CELL) / dw;
+    }
+}
+
 static inline void set_point(int index, float x, float y, float r,
                              float g, float b, float s)
 {
-    int dx = (index / POINTS_PER_CELL) % dw;
-    int dy = (index / POINTS_PER_CELL) / dw;
+    int dx, dy;
+
+    index2cell(index, &dx, &dy);
 
     float fx = (x - dx * RANGE_X) / RANGE_X;
@@ -469 +480 @@
 {
     uint32_t pt = points[index];
-
-    unsigned int dx = (index / POINTS_PER_CELL) % dw;
-    unsigned int dy = (index / POINTS_PER_CELL) / dw;
+    int dx, dy;
+
+    index2cell(index, &dx, &dy);
 
     *s = int2fullrange(pt % RANGE_S, RANGE_S); pt /= RANGE_S;
@@ -937 +948 @@
     }
 
+    bitstack b(MAX_MSG_LEN); /* We cannot declare this before, because
+                              * MAX_MSG_LEN wouldn't be defined. */
+
     /* Autodetect charset if decoding, otherwise switch to CJK. */
     if(dstname)
@@ -973 +987 @@
     /* Precompute bit allocation */
     NUM_CHARACTERS = count_unichars();
+
+    if(dstname)
+    {
+        /* Decoding mode: find each character's index in our character
+         * list, and push it to our wonderful custom bitstream. */
+        for(int i = MAX_MSG_LEN; i--; )
+            b.push(uni2index(unicode_data[i]), NUM_CHARACTERS);
+
+        /* Read width and height from bitstream */
+        src = NULL;
+        width = b.pop(RANGE_W) + 1;
+        height = b.pop(RANGE_H) + 1;
+    }
+    else
+    {
+        /* Argument given: open image for encoding */
+        src = pipi_load(srcname);
+
+        if(!src)
+        {
+            fprintf(stderr, "Error loading %s\n", srcname);
+            return EXIT_FAILURE;
+        }
+
+        width = pipi_get_image_width(src);
+        height = pipi_get_image_height(src);
+    }
+
+    if(width <= 0 || height <= 0 || width > RANGE_W || height > RANGE_H)
+    {
+        fprintf(stderr, "Error: image size %ix%i is out of bounds\n",
+                width, height);
+        return EXIT_FAILURE;
+    }
+
     TOTAL_BITS = MAX_MSG_LEN * logf(NUM_CHARACTERS) / logf(2);
-    HEADER_BITS = logf(MAX_W * MAX_H) / logf(2);
+    HEADER_BITS = logf(RANGE_W * RANGE_H) / logf(2);
     DATA_BITS = TOTAL_BITS - HEADER_BITS;
 #if POINTS_PER_CELL == 1
@@ -988 +1037 @@
     MAX_ITERATIONS = ITERATIONS_PER_POINT * POINTS_PER_CELL * TOTAL_CELLS;
 
-    bitstack b(MAX_MSG_LEN); /* We cannot declare this before, because
-                              * MAX_MSG_LEN wouldn't be defined. */
-
-    if(dstname)
-    {
-        /* Decoding mode: find each character's index in our character
-         * list, and push it to our wonderful custom bitstream. */
-        for(int i = MAX_MSG_LEN; i--; )
-            b.push(uni2index(unicode_data[i]), NUM_CHARACTERS);
-
-        /* Read width and height from bitstream */
-        src = NULL;
-        width = b.pop(MAX_W);
-        height = b.pop(MAX_H);
-    }
-    else
-    {
-        /* Argument given: open image for encoding */
-        src = pipi_load(srcname);
-
-        if(!src)
-        {
-            fprintf(stderr, "Error loading %s\n", srcname);
-            return EXIT_FAILURE;
-        }
-
-        width = pipi_get_image_width(src);
-        height = pipi_get_image_height(src);
-    }
-
     /* Compute "best" w/h ratio */
     dw = 1; dh = TOTAL_CELLS;
@@ -1043 +1062 @@
         fprintf(stderr, "Available characters: %i\n", NUM_CHARACTERS);
         fprintf(stderr, "Available bits: %f\n", TOTAL_BITS);
-        fprintf(stderr, "Maximum image resolution: %ix%i\n", MAX_W, MAX_H);
+        fprintf(stderr, "Width/Height ranges: %ix%i\n", RANGE_W, RANGE_H);
         fprintf(stderr, "Image resolution: %ix%i\n", width, height);
         fprintf(stderr, "Header bits: %f\n", HEADER_BITS);
         fprintf(stderr, "Bits available for data: %f\n", DATA_BITS);
+        fprintf(stderr, "X/Y/Red/Green/Blue/Extra ranges: %i %i %i %i %i %i\n",
+                RANGE_X, RANGE_Y, RANGE_R, RANGE_G, RANGE_B, RANGE_S);
         fprintf(stderr, "Cell bits: %f\n", CELL_BITS);
         fprintf(stderr, "Available cells: %i\n", TOTAL_CELLS);
@@ -1211 +1232 @@
         for(int i = 0; i < npoints; i++)
             b.push(points[i], RANGE_SYXRGB);
-        b.push(height, MAX_H);
-        b.push(width, MAX_W);
+        b.push(height - 1, RANGE_H);
+        b.push(width - 1, RANGE_W);
 
         /* Pop Unicode characters from the bitstream and print them */