* Improve gmathcairo_render_cross_symbol and editor mode support

3 files changed, 136 insertions, 55 deletions

diff --git a/gmathcairo/gmathcairo_renderers.c b/gmathcairo/gmathcairo_renderers.c
index 46a21b8..2e5b403 100644
--- a/gmathcairo/gmathcairo_renderers.c
+++ b/gmathcairo/gmathcairo_renderers.c
@@ -515,7 +515,7 @@ render_boundary (GMathCairoContext *ccontext, GMathSymbol *symbol,
     if (!symbol || !value)
         return NULL;
 
-    return gmathcairo_render_cross_symbol (ccontext, value,
+    return gmathcairo_render_cross_symbol (ccontext, value, NULL,
                                            NULL, symbol->children[1],
                                            NULL, symbol->children[0],
                                            false, true, false, true,
@@ -564,7 +564,7 @@ render_appr (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     if (!symbol)
         return NULL;
 
-    return gmathcairo_render_cross_symbol (ccontext, "→",
+    return gmathcairo_render_cross_symbol (ccontext, "→", NULL,
                                            symbol->children[0],
                                            symbol->children[1],
                                            NULL, NULL,
@@ -743,7 +743,7 @@ render_sum (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     int             x, y, x0, y0;
     float           size_small = size * 0.5;
 
-    if (!symbol || !symbol->children[2])
+    if (!symbol)
         return NULL;
 
     children = g_new0 (GMathBoxed*, 3);
@@ -751,15 +751,24 @@ render_sum (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     dwr = dwt = dwb = 0;
     dhr = dht = dhb = 0;
 
-    children[2] = gmathcairo_render_symbol (ccontext, symbol->children[2],
-                                            size);
-    if (!children[2])
+    if (symbol->children[2])
     {
-        g_free (children);
-        return NULL;
+        children[2] = gmathcairo_render_symbol (ccontext, symbol->children[2],
+                                                size);
+        if (!children[2])
+        {
+            g_free (children);
+            return NULL;
+        }
+        width = dwr = children[2]->box.width;
+        height = dhr = children[2]->box.height;
+    }
+    else
+    {
+        dwr = dhr = 0;
+        width = 0;
+        height = size;
     }
-    width = dwr = children[2]->box.width;
-    height = dhr = children[2]->box.height;
 
     height0 = height;
     width0 = height0 * 0.8;
@@ -883,7 +892,7 @@ render_product (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     int             x, y, x0, y0;
     float           size_small = size * 0.5;
 
-    if (!symbol || !symbol->children[2])
+    if (!symbol)
         return NULL;
 
     children = g_new0 (GMathBoxed*, 3);
@@ -891,15 +900,30 @@ render_product (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     dwr = dwt = dwb = 0;
     dhr = dht = dhb = 0;
 
-    children[2] = gmathcairo_render_symbol (ccontext, symbol->children[2],
-                                            size);
-    if (!children[2])
+    if (symbol->children[2] || ccontext->editor_mode)
     {
-        g_free (children);
-        return NULL;
+        if (symbol->children[2])
+            children[2] = gmathcairo_render_symbol (ccontext,
+                                                    symbol->children[2],
+                                                    size);
+        if (ccontext->editor_mode && !children[2])
+            children[2] = gmathcairo_render_empty (ccontext,
+                                                   symbol->children[2],
+                                                   size);
+        if (!children[2])
+        {
+            g_free (children);
+            return NULL;
+        }
+        width = dwr = children[2]->box.width;
+        height = dhr = children[2]->box.height;
+    }
+    else
+    {
+        dwr = dhr = 0;
+        width = 0;
+        height = size;
     }
-    width = dwr = children[2]->box.width;
-    height = dhr = children[2]->box.height;
 
     height0 = height;
     width0 = height0 * 0.8;
@@ -908,10 +932,12 @@ render_product (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     width += width0;
     width1 = width0;
 
-    if (symbol->children[0])
+    if (symbol->children[0] || ccontext->editor_mode)
     {
-        children[0] = gmathcairo_render_symbol (ccontext, symbol->children[0],
-                                                size_small);
+        if (symbol->children[0])
+            children[0] = gmathcairo_render_symbol (ccontext,
+                                                    symbol->children[0],
+                                                    size_small);
         if (ccontext->editor_mode && !children[0])
             children[0] = gmathcairo_render_empty (ccontext,
                                                    symbol->children[0],
@@ -928,10 +954,12 @@ render_product (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
             height += dhb;
         }
     }
-    if (symbol->children[1])
+    if (symbol->children[1] || ccontext->editor_mode)
     {
-        children[1] = gmathcairo_render_symbol (ccontext, symbol->children[1],
-                                                size_small);
+        if (symbol->children[1])
+            children[1] = gmathcairo_render_symbol (ccontext,
+                                                    symbol->children[1],
+                                                    size_small);
         if (ccontext->editor_mode && !children[1])
             children[1] = gmathcairo_render_empty (ccontext,
                                                    symbol->children[1],
@@ -1023,7 +1051,7 @@ render_integral (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     int             x, y, x0, y0;
     float           size_small = size * 0.5;
 
-    if (!symbol || !symbol->children[2])
+    if (!symbol)
         return NULL;
 
     children = g_new0 (GMathBoxed*, 3);
@@ -1031,15 +1059,24 @@ render_integral (GMathCairoContext *ccontext, GMathSymbol *symbol, float size)
     dwr = dwt = dwb = 0;
     dhr = dht = dhb = 0;
 
-    children[2] = gmathcairo_render_symbol (ccontext, symbol->children[2],
-                                            size);
-    if (!children[2])
+    if (symbol->children[2])
     {
-        g_free (children);
-        return NULL;
+        children[2] = gmathcairo_render_symbol (ccontext, symbol->children[2],
+                                                size);
+        if (!children[2])
+        {
+            g_free (children);
+            return NULL;
+        }
+        width = dwr = children[2]->box.width;
+        height = dhr = children[2]->box.height;
+    }
+    else
+    {
+        dwr = dhr = 0;
+        width = 0;
+        height = size;
     }
-    width = dwr = children[2]->box.width;
-    height = dhr = children[2]->box.height;
 
     height0 = height;
     width0 = height0 * 0.6;
diff --git a/gmathcairo/gmathcairo_utils.c b/gmathcairo/gmathcairo_utils.c
index a4fedac..4946c39 100644
--- a/gmathcairo/gmathcairo_utils.c
+++ b/gmathcairo/gmathcairo_utils.c
@@ -152,6 +152,7 @@ gmathcairo_render_empty (GMathCairoContext *ccontext, GMathSymbol *symbol,
  * The top & bottom children are rendered at half (0.5) the size */
 GMathBoxed*
 gmathcairo_render_cross_symbol (GMathCairoContext *ccontext, gchar *value,
+                                GMathDrawFunc drawfunc,
                                 GMathSymbol *lsymbol, GMathSymbol *rsymbol,
                                 GMathSymbol *tsymbol, GMathSymbol *bsymbol,
                                 bool has_left, bool has_right,
@@ -162,6 +163,7 @@ gmathcairo_render_cross_symbol (GMathCairoContext *ccontext, gchar *value,
     cairo_surface_t *surface;
     GMathBoxed      **children;
     cairo_t         *cr;
+    cairo_surface_t *main_surf;
     int             width, height, width0, height0, width1, height1;
     int             dwl, dhl, dwr, dhr, dwt, dht, dwb, dhb;
     int        	    empty_height;
@@ -169,21 +171,64 @@ gmathcairo_render_cross_symbol (GMathCairoContext *ccontext, gchar *value,
     PangoLayout     *layout;
     float            size_small = size * 0.5;
 
-    if (!value)
+    if (!value && !drawfunc)
         return NULL;
 
     boxed = gmathboxed_new (symbol);
 
     children = g_new0 (GMathBoxed*, 4);
 
-    gmathcairo_get_layout_and_size (ccontext, value, size,
-                                    &layout, &width0, &height0);
-
     dwl = dwr = dwt = dwb = 0;
     dhl = dhr = dht = dhb = 0;
     empty_height = 0;
-    width = width1 = width0;
-    height = height0;
+
+    if (value)
+    {
+        gmathcairo_get_layout_and_size (ccontext, value, size,
+                                        &layout, &width0, &height0);
+        width = width1 = width0;
+        height = height0;
+        if (has_right)
+        {
+            if (rsymbol)
+                children[1] = gmathcairo_render_symbol (ccontext, rsymbol, size);
+            if (ccontext->editor_mode && !children[1])
+                children[1] = gmathcairo_render_empty (ccontext, rsymbol, size);
+            if (children[1])
+            {
+                dwr = children[1]->box.width;
+                dhr = children[1]->box.height;
+                width += dwr;
+                height = MAX (height, dhr);
+            }
+        }
+    }
+    else
+    {
+        if (has_right)
+        {
+            if (rsymbol)
+                children[1] = gmathcairo_render_symbol (ccontext, rsymbol, size);
+            if (ccontext->editor_mode && !children[1])
+                children[1] = gmathcairo_render_empty (ccontext, rsymbol, size);
+        }
+        if (children[1])
+        {
+            dwr = children[1]->box.width;
+            dhr = children[1]->box.height;
+            width = dwr;
+            height = dhr;
+        }
+        else
+        {
+            width = 0;
+            height = size;
+        }
+        height0 = height;
+        width1 = width0 = height0 * 0.6;
+        width += width1;
+        main_surf = (*drawfunc) (width0, height0);
+    }
 
     if (has_left)
     {
@@ -199,20 +244,6 @@ gmathcairo_render_cross_symbol (GMathCairoContext *ccontext, gchar *value,
             height = MAX (height, dhl);
         }
     }
-    if (has_right)
-    {
-        if (rsymbol)
-            children[1] = gmathcairo_render_symbol (ccontext, rsymbol, size);
-        if (ccontext->editor_mode && !children[1])
-            children[1] = gmathcairo_render_empty (ccontext, rsymbol, size);
-        if (children[1])
-        {
-            dwr = children[1]->box.width;
-            dhr = children[1]->box.height;
-            width += dwr;
-            height = MAX (height, dhr);
-        }
-    }
     height1 = height;
     empty_height = (height - height0) / 2;
     if (has_top)
@@ -271,8 +302,17 @@ gmathcairo_render_cross_symbol (GMathCairoContext *ccontext, gchar *value,
     cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
 
     cairo_save (cr);
-    cairo_move_to (cr, x0, y0);
-    pango_cairo_show_layout (cr, layout);
+    if (value)
+    {
+        cairo_move_to (cr, x0, y0);
+        pango_cairo_show_layout (cr, layout);
+    }
+    else
+    {
+        cairo_set_source_surface (cr, main_surf, x0, y0);
+        cairo_paint (cr);
+        cairo_surface_destroy (main_surf);
+    }
     cairo_restore (cr);
 
     if (children[0])
@@ -330,7 +370,8 @@ gmathcairo_render_cross_symbol (GMathCairoContext *ccontext, gchar *value,
     }
 
     /* Free things */
-    g_object_unref (layout);
+    if (value)
+        g_object_unref (layout);
     cairo_destroy (cr);
     g_free (children);
 
diff --git a/include/gmathcairo.h b/include/gmathcairo.h
index 8017ef1..fc99d06 100644
--- a/include/gmathcairo.h
+++ b/include/gmathcairo.h
@@ -44,6 +44,8 @@ typedef GMathBoxed* (*GMathCairoRenderProc) (GMathCairoContext *ccontext,
                                              GMathSymbol *symbol,
                                              float size);
 
+typedef cairo_surface_t* (*GMathDrawFunc) (int width, int height);
+
 struct _GMathCairoContext
 {
     GMathContext    *context; /* Associated GMathContext */
@@ -131,6 +133,7 @@ gmathcairo_get_surface_size (cairo_surface_t *surface, int *width, int *height);
 
 GMathBoxed*
 gmathcairo_render_cross_symbol (GMathCairoContext *ccontext, gchar *value,
+                                GMathDrawFunc drawfunc,
                                 GMathSymbol *lsymbol, GMathSymbol *rsymbol,
                                 GMathSymbol *tsymbol, GMathSymbol *bsymbol,
                                 bool has_left, bool has_right,