]> gitweb.michael.orlitzky.com - libsvgtiny.git/blobdiff - src/svgtiny_gradient.c
prevent division by zero for gradient with no points and add test
[libsvgtiny.git] / src / svgtiny_gradient.c
index 3544f1d199adc9989af193329d848d040755ca36..c36df3207675aed084a8357706ef06efdf55d0bb 100644 (file)
@@ -9,6 +9,7 @@
 #include <math.h>
 #include <string.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "svgtiny.h"
 #include "svgtiny_internal.h"
@@ -30,16 +31,26 @@ static void svgtiny_invert_matrix(float *m, float *inv);
 void svgtiny_find_gradient(const char *id, struct svgtiny_parse_state *state)
 {
        dom_element *gradient;
-       dom_string *id_str;
+       dom_string *id_str, *name;
        dom_exception exc;
 
+       #ifdef GRADIENT_DEBUG
        fprintf(stderr, "svgtiny_find_gradient: id \"%s\"\n", id);
+       #endif
 
        state->linear_gradient_stop_count = 0;
-       state->gradient_x1 = "0%";
-       state->gradient_y1 = "0%";
-       state->gradient_x2 = "100%";
-       state->gradient_y2 = "0%";
+       if (state->gradient_x1 != NULL)
+               dom_string_unref(state->gradient_x1);
+       if (state->gradient_y1 != NULL)
+               dom_string_unref(state->gradient_y1);
+       if (state->gradient_x2 != NULL)
+               dom_string_unref(state->gradient_x2);
+       if (state->gradient_y2 != NULL)
+               dom_string_unref(state->gradient_y2);
+       state->gradient_x1 = dom_string_ref(state->interned_zero_percent);
+       state->gradient_y1 = dom_string_ref(state->interned_zero_percent);
+       state->gradient_x2 = dom_string_ref(state->interned_hundred_percent);
+       state->gradient_y2 = dom_string_ref(state->interned_zero_percent);
        state->gradient_user_space_on_use = false;
        state->gradient_transform.a = 1;
        state->gradient_transform.b = 0;
@@ -48,33 +59,37 @@ void svgtiny_find_gradient(const char *id, struct svgtiny_parse_state *state)
        state->gradient_transform.e = 0;
        state->gradient_transform.f = 0;
        
-       exc = dom_string_create_interned((const uint8_t *) id, strlen(id),
-                                        &id_str);
+       exc = dom_string_create_interned((const uint8_t *) id,
+                       strlen(id), &id_str);
        if (exc != DOM_NO_ERR)
                return;
        
        exc = dom_document_get_element_by_id(state->document, id_str,
                                             &gradient);
        dom_string_unref(id_str);
-       if (exc != DOM_NO_ERR)
-               return;
-
-       if (gradient == NULL) {
+       if (exc != DOM_NO_ERR || gradient == NULL) {
+               #ifdef GRADIENT_DEBUG
                fprintf(stderr, "gradient \"%s\" not found\n", id);
+               #endif
                return;
        }
        
-       exc = dom_node_get_node_name(gradient, &id_str);
+       exc = dom_node_get_node_name(gradient, &name);
        if (exc != DOM_NO_ERR) {
                dom_node_unref(gradient);
                return;
        }
        
-       if (dom_string_isequal(id_str, state->interned_linearGradient))
+       if (dom_string_isequal(name, state->interned_linearGradient))
                svgtiny_parse_linear_gradient(gradient, state);
        
-       dom_string_unref(id_str);
        dom_node_unref(gradient);
+       dom_string_unref(name);
+
+       #ifdef GRADIENT_DEBUG
+       fprintf(stderr, "linear_gradient_stop_count %i\n",
+                       state->linear_gradient_stop_count);
+       #endif
 }
 
 
@@ -88,98 +103,164 @@ svgtiny_code svgtiny_parse_linear_gradient(dom_element *linear,
                struct svgtiny_parse_state *state)
 {
        unsigned int i = 0;
-       dom_element *stop;
        dom_string *attr;
        dom_exception exc;
+       dom_nodelist *stops;
        
        exc = dom_element_get_attribute(linear, state->interned_href, &attr);
        if (exc == DOM_NO_ERR && attr != NULL) {
                if (dom_string_data(attr)[0] == (uint8_t) '#') {
                        char *s = strndup(dom_string_data(attr) + 1,
-                                         dom_string_length(attr) - 1);
+                                         dom_string_byte_length(attr) - 1);
                        svgtiny_find_gradient(s, state);
                        free(s);
                }
                dom_string_unref(attr);
        }
-       
-       for (attr = linear->properties; attr; attr = attr->next) {
-               const char *name = (const char *) attr->name;
-               const char *content = (const char *) attr->children->content;
-               if (strcmp(name, "x1") == 0)
-                       state->gradient_x1 = content;
-               else if (strcmp(name, "y1") == 0)
-                       state->gradient_y1 = content;
-               else if (strcmp(name, "x2") == 0)
-                       state->gradient_x2 = content;
-               else if (strcmp(name, "y2") == 0)
-                       state->gradient_y2 = content;
-               else if (strcmp(name, "gradientUnits") == 0)
-                       state->gradient_user_space_on_use =
-                                       strcmp(content, "userSpaceOnUse") == 0;
-               else if (strcmp(name, "gradientTransform") == 0) {
-                       float a = 1, b = 0, c = 0, d = 1, e = 0, f = 0;
-                       char *s = strdup(content);
-                       if (!s)
-                               return svgtiny_OUT_OF_MEMORY;
-                       svgtiny_parse_transform(s, &a, &b, &c, &d, &e, &f);
-                       free(s);
-                       fprintf(stderr, "transform %g %g %g %g %g %g\n",
-                                       a, b, c, d, e, f);
-                       state->gradient_transform.a = a;
-                       state->gradient_transform.b = b;
-                       state->gradient_transform.c = c;
-                       state->gradient_transform.d = d;
-                       state->gradient_transform.e = e;
-                       state->gradient_transform.f = f;
-               }
-        }
 
-       for (stop = linear->children; stop; stop = stop->next) {
-               float offset = -1;
-               svgtiny_colour color = svgtiny_TRANSPARENT;
+       exc = dom_element_get_attribute(linear, state->interned_x1, &attr);
+       if (exc == DOM_NO_ERR && attr != NULL) {
+               dom_string_unref(state->gradient_x1);
+               state->gradient_x1 = attr;
+               attr = NULL;
+       }
 
-               if (stop->type != XML_ELEMENT_NODE)
-                       continue;
-               if (strcmp((const char *) stop->name, "stop") != 0)
-                       continue;
+       exc = dom_element_get_attribute(linear, state->interned_y1, &attr);
+       if (exc == DOM_NO_ERR && attr != NULL) {
+               dom_string_unref(state->gradient_y1);
+               state->gradient_y1 = attr;
+               attr = NULL;
+       }
+
+       exc = dom_element_get_attribute(linear, state->interned_x2, &attr);
+       if (exc == DOM_NO_ERR && attr != NULL) {
+               dom_string_unref(state->gradient_x2);
+               state->gradient_x2 = attr;
+               attr = NULL;
+       }
 
-               for (attr = stop->properties; attr;
-                               attr = attr->next) {
-                       const char *name = (const char *) attr->name;
-                       const char *content =
-                                       (const char *) attr->children->content;
-                       if (strcmp(name, "offset") == 0)
-                               offset = svgtiny_parse_gradient_offset(content);
-                       else if (strcmp(name, "stop-color") == 0)
-                               svgtiny_parse_color(content, &color, state);
-                       else if (strcmp(name, "style") == 0) {
+       exc = dom_element_get_attribute(linear, state->interned_y2, &attr);
+       if (exc == DOM_NO_ERR && attr != NULL) {
+               dom_string_unref(state->gradient_y2);
+               state->gradient_y2 = attr;
+               attr = NULL;
+       }
+       
+       exc = dom_element_get_attribute(linear, state->interned_gradientUnits,
+                                       &attr);
+       if (exc == DOM_NO_ERR && attr != NULL) {
+               state->gradient_user_space_on_use = 
+                       dom_string_isequal(attr,
+                                          state->interned_userSpaceOnUse);
+               dom_string_unref(attr);
+       }
+       
+       exc = dom_element_get_attribute(linear,
+                                       state->interned_gradientTransform,
+                                       &attr);
+       if (exc == DOM_NO_ERR && attr != NULL) {
+               float a = 1, b = 0, c = 0, d = 1, e = 0, f = 0;
+               char *s = strndup(dom_string_data(attr),
+                                 dom_string_byte_length(attr));
+               if (s == NULL) {
+                       dom_string_unref(attr);
+                       return svgtiny_OUT_OF_MEMORY;
+               }
+               svgtiny_parse_transform(s, &a, &b, &c, &d, &e, &f);
+               free(s);
+               #ifdef GRADIENT_DEBUG
+               fprintf(stderr, "transform %g %g %g %g %g %g\n",
+                       a, b, c, d, e, f);
+               #endif
+               state->gradient_transform.a = a;
+               state->gradient_transform.b = b;
+               state->gradient_transform.c = c;
+               state->gradient_transform.d = d;
+               state->gradient_transform.e = e;
+               state->gradient_transform.f = f;
+               dom_string_unref(attr);
+        }
+       
+       exc = dom_element_get_elements_by_tag_name(linear,
+                                                  state->interned_stop,
+                                                  &stops);
+       if (exc == DOM_NO_ERR && stops != NULL) {
+               uint32_t listlen, stopnr;
+               exc = dom_nodelist_get_length(stops, &listlen);
+               if (exc != DOM_NO_ERR) {
+                       dom_nodelist_unref(stops);
+                       goto no_more_stops;
+               }
+               
+               for (stopnr = 0; stopnr < listlen; ++stopnr) {
+                       dom_element *stop;
+                       float offset = -1;
+                       svgtiny_colour color = svgtiny_TRANSPARENT;
+                       exc = dom_nodelist_item(stops, stopnr,
+                                               (dom_node **) (void *) &stop);
+                       if (exc != DOM_NO_ERR)
+                               continue;
+                       exc = dom_element_get_attribute(stop,
+                                                       state->interned_offset,
+                                                       &attr);
+                       if (exc == DOM_NO_ERR && attr != NULL) {
+                               char *s = strndup(dom_string_data(attr),
+                                                 dom_string_byte_length(attr));
+                               offset = svgtiny_parse_gradient_offset(s);
+                               free(s);
+                               dom_string_unref(attr);
+                       }
+                       exc = dom_element_get_attribute(stop,
+                                                       state->interned_stop_color,
+                                                       &attr);
+                       if (exc == DOM_NO_ERR && attr != NULL) {
+                               svgtiny_parse_color(attr, &color, state);
+                               dom_string_unref(attr);
+                       }
+                       exc = dom_element_get_attribute(stop,
+                                                       state->interned_style,
+                                                       &attr);
+                       if (exc == DOM_NO_ERR && attr != NULL) {
+                               char *content = strndup(dom_string_data(attr),
+                                                       dom_string_byte_length(attr));
                                const char *s;
-                               char *value;
+                               dom_string *value;
                                if ((s = strstr(content, "stop-color:"))) {
                                        s += 11;
                                        while (*s == ' ')
                                                s++;
-                                       value = strndup(s, strcspn(s, "; "));
-                                       svgtiny_parse_color(value, &color,
-                                                       state);
-                                       free(value);
+                                       exc = dom_string_create_interned(
+                                               (const uint8_t *) s,
+                                               strcspn(s, "; "),
+                                               &value);
+                                       if (exc != DOM_NO_ERR && 
+                                           value != NULL) {
+                                               svgtiny_parse_color(value,
+                                                                   &color,
+                                                                   state);
+                                               dom_string_unref(value);
+                                       }
                                }
+                               free(content);
+                               dom_string_unref(attr);
                        }
+                       if (offset != -1 && color != svgtiny_TRANSPARENT) {
+                               #ifdef GRADIENT_DEBUG
+                               fprintf(stderr, "stop %g %x\n", offset, color);
+                               #endif
+                               state->gradient_stop[i].offset = offset;
+                               state->gradient_stop[i].color = color;
+                               i++;
+                       }
+                       dom_node_unref(stop);
+                       if (i == svgtiny_MAX_STOPS)
+                               break;
                }
-
-               if (offset != -1 && color != svgtiny_TRANSPARENT) {
-                       fprintf(stderr, "stop %g %x\n", offset, color);
-                       state->gradient_stop[i].offset = offset;
-                       state->gradient_stop[i].color = color;
-                       i++;
-               }
-
-               if (i == svgtiny_MAX_STOPS)
-                       break;
+               
+               dom_nodelist_unref(stops);
        }
-
-       if (i)
+no_more_stops: 
+       if (i > 0)
                state->linear_gradient_stop_count = i;
 
        return svgtiny_OK;
@@ -245,10 +326,6 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
                        object_x0, object_y0, object_x1, object_y1);
        #endif
 
-       /* compute gradient vector */
-       fprintf(stderr, "x1 %s, y1 %s, x2 %s, y2 %s\n",
-                       state->gradient_x1, state->gradient_y1,
-                       state->gradient_x2, state->gradient_y2);
        if (!state->gradient_user_space_on_use) {
                gradient_x0 = object_x0 +
                                svgtiny_parse_length(state->gradient_x1,
@@ -323,16 +400,17 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
 
        /* invert gradient transform for applying to vertices */
        svgtiny_invert_matrix(&state->gradient_transform.a, trans);
+       #ifdef GRADIENT_DEBUG
        fprintf(stderr, "inverse transform %g %g %g %g %g %g\n",
                        trans[0], trans[1], trans[2], trans[3],
                        trans[4], trans[5]);
+       #endif
 
        /* compute points on the path for triangle vertices */
        /* r, r0, r1 are distance along gradient vector */
        gradient_norm_squared = gradient_dx * gradient_dx +
                                      gradient_dy * gradient_dy;
-       pts = svgtiny_list_create(
-                       sizeof (struct grad_point));
+       pts = svgtiny_list_create(sizeof (struct grad_point));
        if (!pts)
                return svgtiny_OUT_OF_MEMORY;
        for (j = 0; j != n; ) {
@@ -395,11 +473,19 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
                                gradient_norm_squared;
 
                /* determine steps from change in r */
-               steps = ceilf(fabsf(r1 - r0) / 0.05);
+
+               if(isnan(r0) || isnan(r1)) {
+                       steps = 1;
+               } else {
+                       steps = ceilf(fabsf(r1 - r0) / 0.05);
+               }
+
                if (steps == 0)
                        steps = 1;
+               #ifdef GRADIENT_DEBUG
                fprintf(stderr, "r0 %g, r1 %g, steps %i\n",
                                r0, r1, steps);
+               #endif
 
                /* loop through intermediate points */
                for (z = 1; z != steps; z++) {
@@ -424,7 +510,9 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
                        r = ((x_trans - gradient_x0) * gradient_dx +
                                        (y_trans - gradient_y0) * gradient_dy) /
                                        gradient_norm_squared;
+                       #ifdef GRADIENT_DEBUG
                        fprintf(stderr, "(%g %g [%g]) ", x, y, r);
+                       #endif
                        point = svgtiny_list_push(pts);
                        if (!point) {
                                svgtiny_list_free(pts);
@@ -438,15 +526,26 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
                                min_pt = svgtiny_list_size(pts) - 1;
                        }
                }
+               #ifdef GRADIENT_DEBUG
                fprintf(stderr, "\n");
+               #endif
 
                /* next segment start point is this segment end point */
                x0 = x1;
                y0 = y1;
        }
+       #ifdef GRADIENT_DEBUG
        fprintf(stderr, "pts size %i, min_pt %i, min_r %.3f\n",
                        svgtiny_list_size(pts), min_pt, min_r);
+       #endif
 
+        /* There must be at least a single point for the gradient */
+        if (svgtiny_list_size(pts) == 0) {
+            svgtiny_list_free(pts);
+
+            return svgtiny_OK;
+        }
+        
        /* render triangles */
        stop_count = state->linear_gradient_stop_count;
        assert(2 <= stop_count);
@@ -565,7 +664,7 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
 
        /* render triangle vertices with r values for debugging */
        #ifdef GRADIENT_DEBUG
-       for (unsigned int i = 0; i != pts->size; i++) {
+       for (unsigned int i = 0; i != svgtiny_list_size(pts); i++) {
                struct grad_point *point = svgtiny_list_get(pts, i);
                struct svgtiny_shape *shape = svgtiny_add_shape(state);
                if (!shape)