New option to invert y-axis

Replaces all hard coded or implicit desktop coordinate usage with
doc2dt multiplication.

New global preference: Interface > Origin at upper left

https://bugs.launchpad.net/inkscape/+bug/170049

4 files changed, 95 insertions, 31 deletions

diff --git a/src/object/box3d.cpp b/src/object/box3d.cpp
index df95f4f84..7be7c10f7 100644
--- a/src/object/box3d.cpp
+++ b/src/object/box3d.cpp
@@ -149,6 +149,9 @@ void SPBox3D::set(unsigned int key, const gchar* value) {
         case SP_ATTR_INKSCAPE_BOX3D_CORNER0:
             if (value && strcmp(value, "0 : 0 : 0 : 0")) {
                 box->orig_corner0 = Proj::Pt3(value);
+                if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+                    box->orig_corner0[Proj::Y] *= -1;
+                }
                 box->save_corner0 = box->orig_corner0;
                 box3d_position_set(box);
             }
@@ -156,6 +159,9 @@ void SPBox3D::set(unsigned int key, const gchar* value) {
         case SP_ATTR_INKSCAPE_BOX3D_CORNER7:
             if (value && strcmp(value, "0 : 0 : 0 : 0")) {
                 box->orig_corner7 = Proj::Pt3(value);
+                if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+                    box->orig_corner7[Proj::Y] *= -1;
+                }
                 box->save_corner7 = box->orig_corner7;
                 box3d_position_set(box);
             }
@@ -227,8 +233,15 @@ Inkscape::XML::Node* SPBox3D::write(Inkscape::XML::Document *xml_doc, Inkscape::
             }
         }
 
-        gchar *coordstr0 = box->orig_corner0.coord_string();
-        gchar *coordstr7 = box->orig_corner7.coord_string();
+        auto corner0 = box->orig_corner0;
+        auto corner7 = box->orig_corner7;
+        if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+            corner0[Proj::Y] *= -1;
+            corner7[Proj::Y] *= -1;
+        }
+
+        gchar *coordstr0 = corner0.coord_string();
+        gchar *coordstr7 = corner7.coord_string();
         repr->setAttribute("inkscape:corner0", coordstr0);
         repr->setAttribute("inkscape:corner7", coordstr7);
         g_free(coordstr0);
diff --git a/src/object/persp3d.cpp b/src/object/persp3d.cpp
index 2183b6236..05ba5898b 100644
--- a/src/object/persp3d.cpp
+++ b/src/object/persp3d.cpp
@@ -84,6 +84,43 @@ void Persp3D::release() {
     this->getRepr()->removeListenerByData(this);
 }
 
+/**
+ * Apply viewBox and legacy desktop transformation to point loaded from SVG
+ */
+static Proj::Pt2 legacy_transform_forward(Proj::Pt2 pt, SPDocument const *doc) {
+    // Read values are in 'user units'.
+    auto root = doc->getRoot();
+    if (root->viewBox_set) {
+        pt[0] *= root->width.computed / root->viewBox.width();
+        pt[1] *= root->height.computed / root->viewBox.height();
+    }
+
+    // <inkscape:perspective> stores inverted y-axis coordinates
+    if (pt[2] && SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+        pt[1] = doc->getHeight().value("px") - pt[1];
+    }
+
+    return pt;
+}
+
+/**
+ * Apply viewBox and legacy desktop transformation to point to be written to SVG
+ */
+static Proj::Pt2 legacy_transform_backward(Proj::Pt2 pt, SPDocument const *doc) {
+    // <inkscape:perspective> stores inverted y-axis coordinates
+    if (pt[2] && SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+        pt[1] = doc->getHeight().value("px") - pt[1];
+    }
+
+    // Written values are in 'user units'.
+    auto root = doc->getRoot();
+    if (root->viewBox_set) {
+        pt[0] *= root->viewBox.width() / root->width.computed;
+        pt[1] *= root->viewBox.height() / root->height.computed;
+    }
+
+    return pt;
+}
 
 /**
  * Virtual set: set attribute to value.
@@ -92,20 +129,11 @@ void Persp3D::release() {
 //        should we move VPs into their own repr (as it's done for SPStop, e.g.)?
 void Persp3D::set(unsigned key, gchar const *value) {
 
-    // Read values are in 'user units'.
-    double scale_x = 1.0;
-    double scale_y = 1.0;
-    SPRoot *root = document->getRoot();
-    if( root->viewBox_set ) {
-        scale_x = root->width.computed / root->viewBox.width();
-        scale_y = root->height.computed / root->viewBox.height();
-    }
-
     switch (key) {
         case SP_ATTR_INKSCAPE_PERSP3D_VP_X: {
             if (value) {
                 Proj::Pt2 pt (value);
-                Proj::Pt2 ptn ( pt[0]*scale_x, pt[1]*scale_y, pt[2] );
+                Proj::Pt2 ptn = legacy_transform_forward(pt, document);
                 perspective_impl->tmat.set_image_pt( Proj::X, ptn );
             }
             break;
@@ -113,7 +141,7 @@ void Persp3D::set(unsigned key, gchar const *value) {
         case SP_ATTR_INKSCAPE_PERSP3D_VP_Y: {
             if (value) {
                 Proj::Pt2 pt (value);
-                Proj::Pt2 ptn ( pt[0]*scale_x, pt[1]*scale_y, pt[2] );
+                Proj::Pt2 ptn = legacy_transform_forward(pt, document);
                 perspective_impl->tmat.set_image_pt( Proj::Y, ptn );
             }
             break;
@@ -121,7 +149,7 @@ void Persp3D::set(unsigned key, gchar const *value) {
         case SP_ATTR_INKSCAPE_PERSP3D_VP_Z: {
             if (value) {
                 Proj::Pt2 pt (value);
-                Proj::Pt2 ptn ( pt[0]*scale_x, pt[1]*scale_y, pt[2] );
+                Proj::Pt2 ptn = legacy_transform_forward(pt, document);
                 perspective_impl->tmat.set_image_pt( Proj::Z, ptn );
             }
             break;
@@ -129,7 +157,7 @@ void Persp3D::set(unsigned key, gchar const *value) {
         case SP_ATTR_INKSCAPE_PERSP3D_ORIGIN: {
             if (value) {
                 Proj::Pt2 pt (value);
-                Proj::Pt2 ptn ( pt[0]*scale_x, pt[1]*scale_y, pt[2] );
+                Proj::Pt2 ptn = legacy_transform_forward(pt, document);
                 perspective_impl->tmat.set_image_pt( Proj::W, ptn );
             }
             break;
@@ -236,37 +264,32 @@ Inkscape::XML::Node* Persp3D::write(Inkscape::XML::Document *xml_doc, Inkscape::
     }
 
     if (flags & SP_OBJECT_WRITE_EXT) {
-
-        // Written values are in 'user units'.
-        double scale_x = 1.0;
-        double scale_y = 1.0;
-        SPRoot *root = document->getRoot();
-        if( root->viewBox_set ) {
-            scale_x = root->viewBox.width() / root->width.computed;
-            scale_y = root->viewBox.height() / root->height.computed;
-        }
         {
             Proj::Pt2 pt = perspective_impl->tmat.column( Proj::X );
             Inkscape::SVGOStringStream os;
-            os << pt[0] * scale_x  << " : " << pt[1] * scale_y << " : " << pt[2];
+            pt = legacy_transform_backward(pt, document);
+            os << pt[0] << " : " << pt[1] << " : " << pt[2];
             repr->setAttribute("inkscape:vp_x", os.str().c_str());
         }
         {
             Proj::Pt2 pt = perspective_impl->tmat.column( Proj::Y );
             Inkscape::SVGOStringStream os;
-            os << pt[0] * scale_x  << " : " << pt[1] * scale_y << " : " << pt[2];
+            pt = legacy_transform_backward(pt, document);
+            os << pt[0] << " : " << pt[1] << " : " << pt[2];
             repr->setAttribute("inkscape:vp_y", os.str().c_str());
         }
         {
             Proj::Pt2 pt = perspective_impl->tmat.column( Proj::Z );
             Inkscape::SVGOStringStream os;
-            os << pt[0] * scale_x  << " : " << pt[1] * scale_y << " : " << pt[2];
+            pt = legacy_transform_backward(pt, document);
+            os << pt[0] << " : " << pt[1] << " : " << pt[2];
             repr->setAttribute("inkscape:vp_z", os.str().c_str());
         }
         {
             Proj::Pt2 pt = perspective_impl->tmat.column( Proj::W );
             Inkscape::SVGOStringStream os;
-            os << pt[0] * scale_x  << " : " << pt[1] * scale_y << " : " << pt[2];
+            pt = legacy_transform_backward(pt, document);
+            os << pt[0] << " : " << pt[1] << " : " << pt[2];
             repr->setAttribute("inkscape:persp3d-origin", os.str().c_str());
         }
     }
diff --git a/src/object/sp-guide.cpp b/src/object/sp-guide.cpp
index 0b8558230..acb0707d0 100644
--- a/src/object/sp-guide.cpp
+++ b/src/object/sp-guide.cpp
@@ -131,6 +131,12 @@ void SPGuide::set(unsigned int key, const gchar *value) {
             g_strfreev (strarray);
             if (success == 2 && (fabs(newx) > 1e-6 || fabs(newy) > 1e-6)) {
                 Geom::Point direction(newx, newy);
+
+                // <sodipodi:guide> stores inverted y-axis coordinates
+                if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+                    direction[Geom::Y] *= -1.0;
+                }
+
                 direction.normalize();
                 this->normal_to_line = direction;
             } else {
@@ -176,6 +182,11 @@ void SPGuide::set(unsigned int key, const gchar *value) {
                     this->point_on_line = Geom::Point(newx, 0);
                 }
             }
+
+            // <sodipodi:guide> stores inverted y-axis coordinates
+            if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+                this->point_on_line[Geom::Y] = document->getHeight().value("px") - this->point_on_line[Geom::Y];
+            }
         } else {
             // default to (0,0) for bad arguments
             this->point_on_line = Geom::Point(0,0);
@@ -217,6 +228,12 @@ SPGuide *SPGuide::createSPGuide(SPDocument *doc, Geom::Point const &pt1, Geom::P
         }
     }
 
+    // <sodipodi:guide> stores inverted y-axis coordinates
+    if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+        newy = doc->getHeight().value("px") - newy;
+        n[Geom::Y] *= -1.0;
+    }
+
     sp_repr_set_point(repr, "position", Geom::Point( newx, newy ));
     sp_repr_set_point(repr, "orientation", n);
 
@@ -368,6 +385,11 @@ void SPGuide::moveto(Geom::Point const point_on_line, bool const commit)
         double newx = point_on_line.x();
         double newy = point_on_line.y();
 
+        // <sodipodi:guide> stores inverted y-axis coordinates
+        if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+            newy = document->getHeight().value("px") - newy;
+        }
+
         SPRoot *root = document->getRoot();
         if( root->viewBox_set ) {
             // check to see if scaling is uniform
@@ -414,7 +436,14 @@ void SPGuide::set_normal(Geom::Point const normal_to_line, bool const commit)
        case, so that the guide's new position is available for sp_item_rm_unsatisfied_cns. */
     if (commit) {
         //XML Tree being used directly while it shouldn't be
-        sp_repr_set_point(getRepr(), "orientation", normal_to_line);
+        auto normal = normal_to_line;
+
+        // <sodipodi:guide> stores inverted y-axis coordinates
+        if (SP_ACTIVE_DESKTOP && SP_ACTIVE_DESKTOP->is_yaxisdown()) {
+            normal[Geom::Y] *= -1.0;
+        }
+
+        sp_repr_set_point(getRepr(), "orientation", normal);
     }
 
 /*  DISABLED CODE BECAUSE  SPGuideAttachment  IS NOT USE AT THE MOMENT (johan)
diff --git a/src/object/sp-item.cpp b/src/object/sp-item.cpp
index d7c461f92..474687cc6 100644
--- a/src/object/sp-item.cpp
+++ b/src/object/sp-item.cpp
@@ -918,8 +918,7 @@ Geom::OptRect SPItem::desktopGeometricBounds() const
 
 Geom::OptRect SPItem::desktopVisualBounds() const
 {
-    /// @fixme hardcoded desktop transform
-    Geom::Affine m = Geom::Scale(1, -1) * Geom::Translate(0, document->getHeight().value("px"));
+    Geom::Affine const& m = SP_ACTIVE_DESKTOP->doc2dt();
     Geom::OptRect ret = documentVisualBounds();
     if (ret) *ret *= m;
     return ret;