implement drawing of polygons with holes for qt5

3 files changed, 89 insertions, 2 deletions

diff --git a/navit/graphics.c b/navit/graphics.c
index ef0390b92..ec7ea1afd 100644
--- a/navit/graphics.c
+++ b/navit/graphics.c
@@ -1099,6 +1099,47 @@ static void graphics_draw_polygon(struct graphics *gra, struct graphics_gc *gc,
     }
 }
 
+/**
+ * @brief Draw a plain polygon with holes on the display
+ *
+ * @param gra The graphics instance on which to draw
+ * @param gc The graphics context
+ * @param[in] pin An array of points forming the polygon
+ * @param count_in The number of elements inside @p pin
+ * @param hole_count The number of hole polygons to cut out
+ * @param pcount array of [hole_count] integers giving the number of
+ *        points per hole
+ * @param holes array of point arrays for the hole polygons
+ */
+static void graphics_draw_polygon_with_holes(struct graphics *gra, struct graphics_gc *gc, struct point *pin,
+        int count_in, int hole_count, int* ccount, struct point **holes) {
+    if (! gra->meth.draw_polygon_with_holes) {
+        /* TODO: add attr to configure if polygons with holes should be drawn without
+         *       the holes if no graphics support for this is present.
+         */
+        graphics_draw_polygon(gra, gc, pin, count_in);
+        return;
+    } else {
+        struct point * pin_scaled = g_alloca(sizeof (struct point)*count_in);
+        struct point ** holes_scaled = g_alloca(sizeof (struct point *)*hole_count);
+        int a;
+        int b;
+        /* scale the outline */
+        for(a=0; a < count_in; a ++)
+            pin_scaled[a] = graphics_dpi_scale_point(gra,&(pin[a]));
+        /*scale the holes */
+        for(b=0; b < hole_count; b ++) {
+            holes_scaled[b] = g_malloc(sizeof(*(holes_scaled[b])) * ccount[b]);
+            for(a=0; a < ccount[b]; a ++)
+                holes_scaled[b][a] = graphics_dpi_scale_point(gra,&(holes[b][a]));
+        }
+        gra->meth.draw_polygon_with_holes(gra->priv, gc->priv, pin_scaled, count_in, hole_count, ccount, holes_scaled);
+        /* free the hole arrays */
+        for(b=0; b < hole_count; b ++)
+            g_free(holes_scaled[b]);
+    }
+}
+
 void graphics_draw_rectangle_rounded(struct graphics *this_, struct graphics_gc *gc, struct point *plu, int w, int h,
                                      int r, int fill) {
     struct point *p=g_alloca(sizeof(struct point)*(r*4+32));
@@ -2353,6 +2394,7 @@ static void displayitem_draw(struct displayitem *di, void *dummy, struct display
     while (di) {
         int i,count=di->count,mindist=dc->mindist;
         struct displayitem_poly_holes t_holes;
+        t_holes.count=0;
 
         di->z_order=++(gra->current_z_order);
 
@@ -2377,7 +2419,11 @@ static void displayitem_draw(struct displayitem *di, void *dummy, struct display
             count=transform(dc->trans, dc->pro, di->c, pa, count, mindist, 0, NULL);
         switch (e->type) {
         case element_polygon:
-            graphics_draw_polygon_clipped(gra, gc, pa, count);
+            /*TODO: implement a "clipped" version of graphics_draw_polygon_with_holes*/
+            if(t_holes.count > 0)
+                graphics_draw_polygon_with_holes(gra, gc, pa, count, t_holes.count, t_holes.ccount, (struct point **)t_holes.coords);
+            else
+                graphics_draw_polygon_clipped(gra, gc, pa, count);
             break;
         case element_polyline: {
             graphics_gc_set_linewidth(gc, 1);
diff --git a/navit/graphics.h b/navit/graphics.h
index eec44ae14..3ea10e271 100644
--- a/navit/graphics.h
+++ b/navit/graphics.h
@@ -160,6 +160,8 @@ struct graphics_methods {
     int (*show_native_keyboard)(struct graphics_keyboard *kbd);
     void (*hide_native_keyboard)(struct graphics_keyboard *kbd);
     navit_float (*get_dpi)(struct graphics_priv * gr);
+    void (*draw_polygon_with_holes) (struct graphics_priv *gr, struct graphics_gc_priv *gc, struct point *p, int count,
+                                     int hole_count, int* ccount, struct point **holes);
 };
 
 
diff --git a/navit/graphics/qt5/graphics_qt5.cpp b/navit/graphics/qt5/graphics_qt5.cpp
index 535b370dc..10784d6b3 100644
--- a/navit/graphics/qt5/graphics_qt5.cpp
+++ b/navit/graphics/qt5/graphics_qt5.cpp
@@ -418,6 +418,44 @@ static void draw_polygon(struct graphics_priv* gr, struct graphics_gc_priv* gc,
     gr->painter->drawPolygon(polygon);
 }
 
+static void draw_polygon_with_holes (struct graphics_priv *gr, struct graphics_gc_priv *gc, struct point *p, int count,
+                                     int hole_count, int* ccount, struct point **holes) {
+    int i;
+    int j;
+    QPainterPath path;
+    QPainterPath inner;
+    QPolygon polygon;
+    //dbg(lvl_error,"enter gr=%p, gc=%p, (%d, %d) holes %d", gr, gc, p->x, p->y, hole_count);
+    if (gr->painter == NULL)
+        return;
+    gr->painter->setPen(*gc->pen);
+    gr->painter->setBrush(*gc->brush);
+    /* construct outer polygon */
+    for (i = 0; i < count; i++)
+        polygon.putPoints(i, 1, p[i].x, p[i].y);
+    /* add it to outer path */
+    path.addPolygon(polygon);
+    /* construct the polygons for the holes and add them to inner */
+    for(j=0; j<hole_count; j ++) {
+        QPolygon hole;
+        for (i = 0; i < ccount[j]; i++)
+            hole.putPoints(i, 1, holes[j][i].x, holes[j][i].y);
+        inner.addPolygon(hole);
+    }
+    /* intersect */
+    if(hole_count > 0)
+        path = path.subtracted(inner);
+
+    /* if the polygon is transparent, we need to clear it first */
+    if (!gc->brush->isOpaque()) {
+        QPainter::CompositionMode mode = gr->painter->compositionMode();
+        gr->painter->setCompositionMode(QPainter::CompositionMode_Clear);
+        gr->painter->drawPath(path);
+        gr->painter->setCompositionMode(mode);
+    }
+    gr->painter->drawPath(path);
+}
+
 static void draw_rectangle(struct graphics_priv* gr, struct graphics_gc_priv* gc, struct point* p, int w, int h) {
     //	dbg(lvl_debug,"gr=%p gc=%p %d,%d,%d,%d", gr, gc, p->x, p->y, w, h);
     if (gr->painter == NULL)
@@ -851,7 +889,8 @@ static struct graphics_methods graphics_methods = {
     NULL, //set_attr
     NULL, //show_native_keyboard
     NULL, //hide_native_keyboard
-    get_dpi
+    get_dpi,
+    draw_polygon_with_holes
 };
 
 /* create new graphics context on given context */