prevent division by zero for gradient with no points and add test

[libsvgtiny.git] / src / svgtiny_gradient.c

diff --git a/src/svgtiny_gradient.c b/src/svgtiny_gradient.c
index 8103c14454a5dabfab6bd3cc1c434ca9f3ad0f14..c36df3207675aed084a8357706ef06efdf55d0bb 100644 (file)
--- a/src/svgtiny_gradient.c
+++ b/src/svgtiny_gradient.c
@@ -31,7 +31,7 @@ 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
@@ -59,35 +59,32 @@ 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",
@@ -413,8 +410,7 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int n,
        /* 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; ) {
@@ -543,6 +539,13 @@ svgtiny_code svgtiny_add_path_linear_gradient(float *p, unsigned int 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);
@@ -661,7 +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)