moving trunk for module inkscape

(bzr r1)

1 files changed, 1006 insertions, 0 deletions

diff --git a/src/desktop-style.cpp b/src/desktop-style.cpp
new file mode 100644
index 000000000..540fd1637
--- /dev/null
+++ b/src/desktop-style.cpp
@@ -0,0 +1,1006 @@
+#define __SP_DESKTOP_STYLE_C__
+
+/** \file
+ * Desktop style management
+ *
+ * Authors:
+ *   bulia byak
+ *
+ * Copyright (C) 2004 authors
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include "desktop.h"
+#include "color-rgba.h"
+#include "svg/css-ostringstream.h"
+#include "svg/svg.h"
+#include "selection.h"
+#include "sp-tspan.h"
+#include "sp-textpath.h"
+#include "inkscape.h"
+#include "style.h"
+#include "prefs-utils.h"
+#include "sp-use.h"
+#include "sp-flowtext.h"
+#include "sp-flowregion.h"
+#include "sp-flowdiv.h"
+#include "sp-linear-gradient.h"
+#include "sp-radial-gradient.h"
+#include "sp-pattern.h"
+#include "xml/repr.h"
+#include "libnrtype/font-style-to-pos.h"
+
+#include "desktop-style.h"
+
+/**
+ * Set color on selection on desktop.
+ */
+void
+sp_desktop_set_color(SPDesktop *desktop, ColorRGBA const &color, bool is_relative, bool fill)
+{
+    /// \todo relative color setting
+    if (is_relative) {
+        g_warning("FIXME: relative color setting not yet implemented");
+        return;
+    }
+
+    guint32 rgba = SP_RGBA32_F_COMPOSE(color[0], color[1], color[2], color[3]);
+    gchar b[64];
+    sp_svg_write_color(b, 64, rgba);
+    SPCSSAttr *css = sp_repr_css_attr_new();
+    if (fill) {
+        sp_repr_css_set_property(css, "fill", b);
+        Inkscape::CSSOStringStream osalpha;
+        osalpha << color[3];
+        sp_repr_css_set_property(css, "fill-opacity", osalpha.str().c_str());
+    } else {
+        sp_repr_css_set_property(css, "stroke", b);
+        Inkscape::CSSOStringStream osalpha;
+        osalpha << color[3];
+        sp_repr_css_set_property(css, "stroke-opacity", osalpha.str().c_str());
+    }
+
+    sp_desktop_set_style(desktop, css);
+
+    sp_repr_css_attr_unref(css);
+}
+
+/**
+ * Apply style on object and children, recursively.
+ */
+void
+sp_desktop_apply_css_recursive(SPObject *o, SPCSSAttr *css, bool skip_lines)
+{
+    // non-items should not have style
+    if (!SP_IS_ITEM(o))
+        return;
+
+    // 1. tspans with role=line are not regular objects in that they are not supposed to have style of their own,
+    // but must always inherit from the parent text. Same for textPath.
+    // However, if the line tspan or textPath contains some style (old file?), we reluctantly set our style to it too.
+
+    // 2. Generally we allow setting style on clones, but when it's inside flowRegion, do not touch
+    // it, be it clone or not; it's just styleless shape (because that's how Inkscape does
+    // flowtext). 
+
+    if (!(skip_lines
+          && ((SP_IS_TSPAN(o) && SP_TSPAN(o)->role == SP_TSPAN_ROLE_LINE)
+              || SP_IS_FLOWDIV(o)
+              || SP_IS_FLOWPARA(o)
+              || SP_IS_TEXTPATH(o))
+          && !SP_OBJECT_REPR(o)->attribute("style"))
+        &&
+        !(SP_IS_FLOWREGION(o) ||
+          SP_IS_FLOWREGIONEXCLUDE(o) ||
+          (SP_IS_USE(o) &&
+           SP_OBJECT_PARENT(o) &&
+           (SP_IS_FLOWREGION(SP_OBJECT_PARENT(o)) ||
+            SP_IS_FLOWREGIONEXCLUDE(SP_OBJECT_PARENT(o))
+           )
+          )
+         )
+        ) {
+
+        SPCSSAttr *css_set = sp_repr_css_attr_new();
+        sp_repr_css_merge(css_set, css);
+
+        // Scale the style by the inverse of the accumulated parent transform in the paste context.
+        {
+            NR::Matrix const local(sp_item_i2doc_affine(SP_ITEM(o)));
+            double const ex(NR::expansion(local));
+            if ( ( ex != 0. )
+                 && ( ex != 1. ) ) {
+                sp_css_attr_scale(css_set, 1/ex);
+            }
+        }
+
+        sp_repr_css_change(SP_OBJECT_REPR(o), css_set, "style");
+
+        sp_repr_css_attr_unref(css_set);
+    }
+
+    // setting style on child of clone spills into the clone original (via shared repr), don't do it!
+    if (SP_IS_USE(o))
+        return;
+
+    for (SPObject *child = sp_object_first_child(SP_OBJECT(o)) ; child != NULL ; child = SP_OBJECT_NEXT(child) ) {
+        if (sp_repr_css_property(css, "opacity", NULL) != NULL) {
+            // Unset properties which are accumulating and thus should not be set recursively.
+            // For example, setting opacity 0.5 on a group recursively would result in the visible opacity of 0.25 for an item in the group.
+            SPCSSAttr *css_recurse = sp_repr_css_attr_new();
+            sp_repr_css_merge(css_recurse, css);
+            sp_repr_css_set_property(css_recurse, "opacity", NULL);
+            sp_desktop_apply_css_recursive(child, css_recurse, skip_lines);
+            sp_repr_css_attr_unref(css_recurse);
+        } else {
+            sp_desktop_apply_css_recursive(child, css, skip_lines);
+        }
+    }
+}
+
+/**
+ * Apply style on selection on desktop.
+ */
+void
+sp_desktop_set_style(SPDesktop *desktop, SPCSSAttr *css, bool change, bool write_current)
+{
+    if (write_current) {
+// 1. Set internal value
+        sp_repr_css_merge(desktop->current, css);
+
+// 1a. Write to prefs; make a copy and unset any URIs first
+        SPCSSAttr *css_write = sp_repr_css_attr_new();
+        sp_repr_css_merge(css_write, css);
+        sp_css_attr_unset_uris(css_write);
+        sp_repr_css_change(inkscape_get_repr(INKSCAPE, "desktop"), css_write, "style");
+        sp_repr_css_attr_unref(css_write);
+    }
+
+    if (!change)
+        return;
+
+// 2. Emit signal
+    bool intercepted = desktop->_set_style_signal.emit(css);
+
+/** \todo
+ * FIXME: in set_style, compensate pattern and gradient fills, stroke width, 
+ * rect corners, font size for the object's own transform so that pasting 
+ * fills does not depend on preserve/optimize.
+ */
+
+// 3. If nobody has intercepted the signal, apply the style to the selection
+    if (!intercepted) {
+        for (GSList const *i = desktop->selection->itemList(); i != NULL; i = i->next) {
+            /// \todo if the style is text-only, apply only to texts?
+            sp_desktop_apply_css_recursive(SP_OBJECT(i->data), css, true);
+        }
+    }
+}
+
+/**
+ * Return the desktop's current style.
+ */
+SPCSSAttr *
+sp_desktop_get_style(SPDesktop *desktop, bool with_text)
+{
+    SPCSSAttr *css = sp_repr_css_attr_new();
+    sp_repr_css_merge(css, desktop->current);
+    if (!css->attributeList()) {
+        sp_repr_css_attr_unref(css);
+        return NULL;
+    } else {
+        if (!with_text) {
+            css = sp_css_attr_unset_text(css);
+        }
+        return css;
+    }
+}
+
+/**
+ * Return the desktop's current color.
+ */
+guint32
+sp_desktop_get_color(SPDesktop *desktop, bool is_fill)
+{
+    guint32 r = 0; // if there's no color, return black
+    gchar const *property = sp_repr_css_property(desktop->current,
+                                                 is_fill ? "fill" : "stroke",
+                                                 "#000");
+
+    if (desktop->current && property) { // if there is style and the property in it,
+        if (strncmp(property, "url", 3)) { // and if it's not url,
+            // read it
+            r = sp_svg_read_color(property, r);
+        }
+    }
+
+    return r;
+}
+
+/**
+ * Apply the desktop's current style or the tool style to repr.
+ */
+void
+sp_desktop_apply_style_tool(SPDesktop *desktop, Inkscape::XML::Node *repr, char const *tool, bool with_text)
+{
+    SPCSSAttr *css_current = sp_desktop_get_style(desktop, with_text);
+    if ((prefs_get_int_attribute(tool, "usecurrent", 0) != 0) && css_current) {
+        sp_repr_css_set(repr, css_current, "style");
+    } else {
+        Inkscape::XML::Node *tool_repr = inkscape_get_repr(INKSCAPE, tool);
+        if (tool_repr) {
+            SPCSSAttr *css = sp_repr_css_attr_inherited(tool_repr, "style");
+            sp_repr_css_set(repr, css, "style");
+            sp_repr_css_attr_unref(css);
+        }
+    }
+    if (css_current) {
+        sp_repr_css_attr_unref(css_current);
+    }
+}
+
+/**
+ * Returns the font size (in SVG pixels) of the text tool style (if text 
+ * tool uses its own style) or desktop style (otherwise).
+*/
+double
+sp_desktop_get_font_size_tool(SPDesktop *desktop)
+{
+    gchar const *desktop_style = inkscape_get_repr(INKSCAPE, "desktop")->attribute("style");
+    gchar const *style_str = NULL;
+    if ((prefs_get_int_attribute("tools.text", "usecurrent", 0) != 0) && desktop_style) {
+        style_str = desktop_style;
+    } else {
+        Inkscape::XML::Node *tool_repr = inkscape_get_repr(INKSCAPE, "tools.text");
+        if (tool_repr) {
+            style_str = tool_repr->attribute("style");
+        }
+    }
+
+    double ret = 12;
+    if (style_str) {
+        SPStyle *style = sp_style_new();
+        sp_style_merge_from_style_string(style, style_str);
+        ret = style->font_size.computed;
+        sp_style_unref(style);
+    }
+    return ret;
+}
+
+/** Determine average stroke width, simple method */
+// see TODO in dialogs/stroke-style.cpp on how to get rid of this eventually
+gdouble
+stroke_average_width (GSList const *objects)
+{
+    if (g_slist_length ((GSList *) objects) == 0)
+        return NR_HUGE;
+
+    gdouble avgwidth = 0.0;
+    bool notstroked = true;
+    int n_notstroked = 0;
+
+    for (GSList const *l = objects; l != NULL; l = l->next) {
+        if (!SP_IS_ITEM (l->data))
+            continue;
+
+        NR::Matrix i2d = sp_item_i2d_affine (SP_ITEM(l->data));
+
+        SPObject *object = SP_OBJECT(l->data);
+
+        if ( object->style->stroke.type == SP_PAINT_TYPE_NONE ) {
+            ++n_notstroked;   // do not count nonstroked objects
+            continue;
+        } else {
+            notstroked = false;
+        }
+
+        avgwidth += SP_OBJECT_STYLE (object)->stroke_width.computed * i2d.expansion();
+    }
+
+    if (notstroked)
+        return NR_HUGE;
+
+    return avgwidth / (g_slist_length ((GSList *) objects) - n_notstroked);
+}
+
+/**
+ * Write to style_res the average fill or stroke of list of objects, if applicable.
+ */
+int
+objects_query_fillstroke (GSList *objects, SPStyle *style_res, bool const isfill)
+{
+    if (g_slist_length(objects) == 0) {
+        /* No objects, set empty */
+        return QUERY_STYLE_NOTHING;
+    }
+
+    SPIPaint *paint_res = isfill? &style_res->fill : &style_res->stroke;
+    paint_res->type = SP_PAINT_TYPE_IMPOSSIBLE;
+    paint_res->set = TRUE;
+
+    gfloat c[4];
+    c[0] = c[1] = c[2] = c[3] = 0.0;
+    gint num = 0;
+
+    gfloat prev[4];
+    prev[0] = prev[1] = prev[2] = prev[3] = 0.0;
+    bool same_color = true;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        SPIPaint *paint = isfill? &style->fill : &style->stroke;
+
+        // We consider paint "effectively set" for anything within text hierarchy
+        SPObject *parent = SP_OBJECT_PARENT (obj);
+        bool paint_effectively_set = paint->set || (SP_IS_TEXT(parent) || SP_IS_TEXTPATH(parent) || SP_IS_TSPAN(parent) || SP_IS_FLOWTEXT(parent) || SP_IS_FLOWDIV(parent) || SP_IS_FLOWPARA(parent) || SP_IS_FLOWTSPAN(parent) || SP_IS_FLOWLINE(parent));
+
+        // 1. Bail out with QUERY_STYLE_MULTIPLE_DIFFERENT if necessary
+
+        if ((paint_res->type != SP_PAINT_TYPE_IMPOSSIBLE) && (paint->type != paint_res->type || (paint_res->set != paint_effectively_set))) {
+            return QUERY_STYLE_MULTIPLE_DIFFERENT;  // different types of paint
+        }
+
+        if (paint_res->set && paint->set && paint_res->type == SP_PAINT_TYPE_PAINTSERVER) {
+            // both previous paint and this paint were a server, see if the servers are compatible
+
+            SPPaintServer *server_res = isfill? SP_STYLE_FILL_SERVER (style_res) : SP_STYLE_STROKE_SERVER (style_res);
+            SPPaintServer *server = isfill? SP_STYLE_FILL_SERVER (style) : SP_STYLE_STROKE_SERVER (style);
+
+            if (SP_IS_LINEARGRADIENT (server_res)) {
+
+                if (!SP_IS_LINEARGRADIENT(server))
+                   return QUERY_STYLE_MULTIPLE_DIFFERENT;  // different kind of server
+
+                SPGradient *vector = sp_gradient_get_vector ( SP_GRADIENT (server), FALSE );
+                SPGradient *vector_res = sp_gradient_get_vector ( SP_GRADIENT (server_res), FALSE );
+                if (vector_res != vector)
+                   return QUERY_STYLE_MULTIPLE_DIFFERENT;  // different gradient vectors
+
+            } else if (SP_IS_RADIALGRADIENT (server_res)) {
+
+                if (!SP_IS_RADIALGRADIENT(server))
+                   return QUERY_STYLE_MULTIPLE_DIFFERENT;  // different kind of server
+
+                SPGradient *vector = sp_gradient_get_vector ( SP_GRADIENT (server), FALSE );
+                SPGradient *vector_res = sp_gradient_get_vector ( SP_GRADIENT (server_res), FALSE );
+                if (vector_res != vector)
+                   return QUERY_STYLE_MULTIPLE_DIFFERENT;  // different gradient vectors
+
+            } else if (SP_IS_PATTERN (server_res)) {
+
+                if (!SP_IS_PATTERN(server))
+                   return QUERY_STYLE_MULTIPLE_DIFFERENT;  // different kind of server
+ 
+                SPPattern *pat = pattern_getroot (SP_PATTERN (server));
+                SPPattern *pat_res = pattern_getroot (SP_PATTERN (server_res));
+                if (pat_res != pat)
+                   return QUERY_STYLE_MULTIPLE_DIFFERENT;  // different pattern roots
+            }
+        }
+
+        // 2. Sum color, copy server from paint to paint_res
+
+        if (paint_res->set && paint_effectively_set && paint->type == SP_PAINT_TYPE_COLOR) {
+
+            gfloat d[3];
+            sp_color_get_rgb_floatv (&paint->value.color, d);
+
+            // Check if this color is the same as previous
+            if (paint_res->type == SP_PAINT_TYPE_IMPOSSIBLE) {
+                prev[0] = d[0];
+                prev[1] = d[1];
+                prev[2] = d[2];
+                prev[3] = d[3];
+            } else {
+                if (same_color && (prev[0] != d[0] || prev[1] != d[1] || prev[2] != d[2] || prev[3] != d[3]))
+                    same_color = false;
+            }
+
+            // average color
+            c[0] += d[0];
+            c[1] += d[1];
+            c[2] += d[2];
+            c[3] += SP_SCALE24_TO_FLOAT (isfill? style->fill_opacity.value : style->stroke_opacity.value);
+            num ++;
+        }
+
+       if (paint_res->set && paint->set && paint->type == SP_PAINT_TYPE_PAINTSERVER) { // copy the server
+           if (isfill) {
+               SP_STYLE_FILL_SERVER (style_res) = SP_STYLE_FILL_SERVER (style);
+           } else {
+               SP_STYLE_STROKE_SERVER (style_res) = SP_STYLE_STROKE_SERVER (style);
+           }
+       }
+       paint_res->type = paint->type;
+       paint_res->set = paint_effectively_set;
+       style_res->fill_rule.computed = style->fill_rule.computed; // no averaging on this, just use the last one
+    }
+
+    // After all objects processed, divide the color if necessary and return
+    if (paint_res->set && paint_res->type == SP_PAINT_TYPE_COLOR) { // set the color
+        g_assert (num >= 1);
+
+        c[0] /= num;
+        c[1] /= num;
+        c[2] /= num;
+        c[3] /= num;
+        sp_color_set_rgb_float(&paint_res->value.color, c[0], c[1], c[2]);
+        if (isfill) {
+            style_res->fill_opacity.value = SP_SCALE24_FROM_FLOAT (c[3]);
+        } else {
+            style_res->stroke_opacity.value = SP_SCALE24_FROM_FLOAT (c[3]);
+        }
+        if (num > 1) {
+            if (same_color)
+                return QUERY_STYLE_MULTIPLE_SAME;
+            else 
+                return QUERY_STYLE_MULTIPLE_AVERAGED;
+        } else {
+            return QUERY_STYLE_SINGLE;
+        }
+    }
+
+    // Not color
+    if (g_slist_length(objects) > 1) {
+        return QUERY_STYLE_MULTIPLE_SAME;
+    } else {
+        return QUERY_STYLE_SINGLE;
+    }
+}
+
+/**
+ * Write to style_res the average opacity of a list of objects.
+ */
+int
+objects_query_opacity (GSList *objects, SPStyle *style_res)
+{
+    if (g_slist_length(objects) == 0) {
+        /* No objects, set empty */
+        return QUERY_STYLE_NOTHING;
+    }
+
+    gdouble opacity_sum = 0;
+    gdouble opacity_prev = -1;
+    bool same_opacity = true;
+    guint opacity_items = 0;
+
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        double opacity = SP_SCALE24_TO_FLOAT(style->opacity.value);
+        opacity_sum += opacity;
+        if (opacity_prev != -1 && opacity != opacity_prev)
+            same_opacity = false;
+        opacity_prev = opacity;
+        opacity_items ++;
+    }
+    if (opacity_items > 1)
+        opacity_sum /= opacity_items;
+
+    style_res->opacity.value = SP_SCALE24_FROM_FLOAT(opacity_sum);
+
+    if (opacity_items == 0) {
+        return QUERY_STYLE_NOTHING;
+    } else if (opacity_items == 1) {
+        return QUERY_STYLE_SINGLE;
+    } else {
+        if (same_opacity)
+            return QUERY_STYLE_MULTIPLE_SAME;
+        else 
+            return QUERY_STYLE_MULTIPLE_AVERAGED;
+    }
+}
+
+/**
+ * Write to style_res the average stroke width of a list of objects.
+ */
+int
+objects_query_strokewidth (GSList *objects, SPStyle *style_res)
+{
+    if (g_slist_length(objects) == 0) {
+        /* No objects, set empty */
+        return QUERY_STYLE_NOTHING;
+    }
+
+    gdouble avgwidth = 0.0;
+
+    gdouble prev_sw = -1;
+    bool same_sw = true;
+
+    int n_stroked = 0;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+        if (!SP_IS_ITEM(obj)) continue;
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        if ( style->stroke.type == SP_PAINT_TYPE_NONE ) {
+            continue;
+        } 
+
+        n_stroked ++;
+
+        NR::Matrix i2d = sp_item_i2d_affine (SP_ITEM(obj));
+        double sw = style->stroke_width.computed * i2d.expansion();
+
+        if (prev_sw != -1 && fabs(sw - prev_sw) > 1e-3)
+            same_sw = false;
+        prev_sw = sw;
+
+        avgwidth += sw;
+    }
+
+    if (n_stroked > 1)
+        avgwidth /= (n_stroked);
+
+    style_res->stroke_width.computed = avgwidth;
+    style_res->stroke_width.set = true;
+
+    if (n_stroked == 0) {
+        return QUERY_STYLE_NOTHING;
+    } else if (n_stroked == 1) {
+        return QUERY_STYLE_SINGLE;
+    } else {
+        if (same_sw)
+            return QUERY_STYLE_MULTIPLE_SAME;
+        else 
+            return QUERY_STYLE_MULTIPLE_AVERAGED;
+    }
+}
+
+/**
+ * Write to style_res the average miter limit of a list of objects.
+ */
+int
+objects_query_miterlimit (GSList *objects, SPStyle *style_res)
+{
+    if (g_slist_length(objects) == 0) {
+        /* No objects, set empty */
+        return QUERY_STYLE_NOTHING;
+    }
+
+    gdouble avgml = 0.0;
+    int n_stroked = 0;
+
+    gdouble prev_ml = -1;
+    bool same_ml = true;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+        if (!SP_IS_ITEM(obj)) continue;
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        if ( style->stroke.type == SP_PAINT_TYPE_NONE ) {
+            continue;
+        } 
+
+        n_stroked ++;
+
+        if (prev_ml != -1 && fabs(style->stroke_miterlimit.value - prev_ml) > 1e-3)
+            same_ml = false;
+        prev_ml = style->stroke_miterlimit.value;
+
+        avgml += style->stroke_miterlimit.value;
+    }
+
+    if (n_stroked > 1)
+        avgml /= (n_stroked);
+
+    style_res->stroke_miterlimit.value = avgml;
+    style_res->stroke_miterlimit.set = true;
+
+    if (n_stroked == 0) {
+        return QUERY_STYLE_NOTHING;
+    } else if (n_stroked == 1) {
+        return QUERY_STYLE_SINGLE;
+    } else {
+        if (same_ml)
+            return QUERY_STYLE_MULTIPLE_SAME;
+        else 
+            return QUERY_STYLE_MULTIPLE_AVERAGED;
+    }
+}
+
+/**
+ * Write to style_res the stroke cap of a list of objects.
+ */
+int
+objects_query_strokecap (GSList *objects, SPStyle *style_res)
+{
+    if (g_slist_length(objects) == 0) {
+        /* No objects, set empty */
+        return QUERY_STYLE_NOTHING;
+    }
+
+    int cap = -1;
+    gdouble prev_cap = -1;
+    bool same_cap = true;
+    int n_stroked = 0;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+        if (!SP_IS_ITEM(obj)) continue;
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        if ( style->stroke.type == SP_PAINT_TYPE_NONE ) {
+            continue;
+        } 
+
+        n_stroked ++;
+
+        if (prev_cap != -1 && style->stroke_linecap.value != prev_cap)
+            same_cap = false;
+        prev_cap = style->stroke_linecap.value;
+
+        cap = style->stroke_linecap.value;
+    }
+
+    style_res->stroke_linecap.value = cap;
+    style_res->stroke_linecap.set = true;
+
+    if (n_stroked == 0) {
+        return QUERY_STYLE_NOTHING;
+    } else if (n_stroked == 1) {
+        return QUERY_STYLE_SINGLE;
+    } else {
+        if (same_cap)
+            return QUERY_STYLE_MULTIPLE_SAME;
+        else 
+            return QUERY_STYLE_MULTIPLE_DIFFERENT;
+    }
+}
+
+/**
+ * Write to style_res the stroke join of a list of objects.
+ */
+int
+objects_query_strokejoin (GSList *objects, SPStyle *style_res)
+{
+    if (g_slist_length(objects) == 0) {
+        /* No objects, set empty */
+        return QUERY_STYLE_NOTHING;
+    }
+
+    int join = -1;
+    gdouble prev_join = -1;
+    bool same_join = true;
+    int n_stroked = 0;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+        if (!SP_IS_ITEM(obj)) continue;
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        if ( style->stroke.type == SP_PAINT_TYPE_NONE ) {
+            continue;
+        } 
+
+        n_stroked ++;
+
+        if (prev_join != -1 && style->stroke_linejoin.value != prev_join)
+            same_join = false;
+        prev_join = style->stroke_linejoin.value;
+
+        join = style->stroke_linejoin.value;
+    }
+
+    style_res->stroke_linejoin.value = join;
+    style_res->stroke_linejoin.set = true;
+
+    if (n_stroked == 0) {
+        return QUERY_STYLE_NOTHING;
+    } else if (n_stroked == 1) {
+        return QUERY_STYLE_SINGLE;
+    } else {
+        if (same_join)
+            return QUERY_STYLE_MULTIPLE_SAME;
+        else 
+            return QUERY_STYLE_MULTIPLE_DIFFERENT;
+    }
+}
+
+/**
+ * Write to style_res the average font size and spacing of objects.
+ */
+int
+objects_query_fontnumbers (GSList *objects, SPStyle *style_res)
+{
+    bool different = false;
+
+    double size = 0;
+    double letterspacing = 0;
+    double linespacing = 0;
+    bool linespacing_normal = false;
+    bool letterspacing_normal = false;
+
+    double size_prev = 0;
+    double letterspacing_prev = 0;
+    double linespacing_prev = 0;
+
+    /// \todo FIXME: add word spacing, kerns? rotates?
+
+    int texts = 0;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+
+        if (!SP_IS_TEXT(obj) && !SP_IS_FLOWTEXT(obj)
+            && !SP_IS_TSPAN(obj) && !SP_IS_TEXTPATH(obj)
+            && !SP_IS_FLOWDIV(obj) && !SP_IS_FLOWPARA(obj) && !SP_IS_FLOWTSPAN(obj))
+            continue;
+
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        texts ++;
+        size += style->font_size.computed * NR::expansion(sp_item_i2d_affine(SP_ITEM(obj))); /// \todo FIXME: we assume non-% units here
+
+        if (style->letter_spacing.normal) {
+            if (!different && (letterspacing_prev == 0 || letterspacing_prev == letterspacing))
+                letterspacing_normal = true;
+        } else {
+            letterspacing += style->letter_spacing.computed; /// \todo FIXME: we assume non-% units here
+            letterspacing_normal = false;
+        }
+
+        double linespacing_current; 
+        if (style->line_height.normal) {
+            linespacing_current = Inkscape::Text::Layout::LINE_HEIGHT_NORMAL;
+            if (!different && (linespacing_prev == 0 || linespacing_prev == linespacing_current))
+                linespacing_normal = true;
+        } else if (style->line_height.unit == SP_CSS_UNIT_PERCENT || style->font_size.computed == 0) {
+            linespacing_current = style->line_height.value;
+            linespacing_normal = false;
+        } else { // we need % here
+            linespacing_current = style->line_height.computed / style->font_size.computed;
+            linespacing_normal = false;
+        }
+        linespacing += linespacing_current;
+
+        if ((size_prev != 0 && style->font_size.computed != size_prev) ||
+            (letterspacing_prev != 0 && style->letter_spacing.computed != letterspacing_prev) ||
+            (linespacing_prev != 0 && linespacing_current != linespacing_prev)) {
+            different = true;
+        }
+
+        size_prev = style->font_size.computed;
+        letterspacing_prev = style->letter_spacing.computed;
+        linespacing_prev = linespacing_current;
+
+        // FIXME: we must detect MULTIPLE_DIFFERENT for these too
+        style_res->text_anchor.computed = style->text_anchor.computed;
+        style_res->writing_mode.computed = style->writing_mode.computed;
+    }
+
+    if (texts == 0)
+        return QUERY_STYLE_NOTHING;
+
+    if (texts > 1) {
+        size /= texts;
+        letterspacing /= texts;
+        linespacing /= texts;
+    }
+
+    style_res->font_size.computed = size;
+    style_res->font_size.type = SP_FONT_SIZE_LENGTH;
+
+    style_res->letter_spacing.normal = letterspacing_normal;
+    style_res->letter_spacing.computed = letterspacing;
+
+    style_res->line_height.normal = linespacing_normal;
+    style_res->line_height.computed = linespacing;
+    style_res->line_height.value = linespacing;
+    style_res->line_height.unit = SP_CSS_UNIT_PERCENT;
+
+    if (texts > 1) {
+        if (different) {
+            return QUERY_STYLE_MULTIPLE_AVERAGED;
+        } else {
+            return QUERY_STYLE_MULTIPLE_SAME;
+        }
+    } else {
+        return QUERY_STYLE_SINGLE;
+    }
+}
+
+/**
+ * Write to style_res the average font style of objects.
+ */
+int
+objects_query_fontstyle (GSList *objects, SPStyle *style_res)
+{
+    bool different = false;
+    bool set = false;
+
+    int texts = 0;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+
+        if (!SP_IS_TEXT(obj) && !SP_IS_FLOWTEXT(obj)
+            && !SP_IS_TSPAN(obj) && !SP_IS_TEXTPATH(obj)
+            && !SP_IS_FLOWDIV(obj) && !SP_IS_FLOWPARA(obj) && !SP_IS_FLOWTSPAN(obj))
+            continue;
+
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        texts ++;
+
+        if (set && 
+            font_style_to_pos(*style_res).signature() != font_style_to_pos(*style).signature() ) {
+            different = true;  // different styles
+        }
+
+        set = TRUE;
+        style_res->font_weight.value = style_res->font_weight.computed = style->font_weight.computed;
+        style_res->font_style.value = style_res->font_style.computed = style->font_style.computed;
+        style_res->font_stretch.value = style_res->font_stretch.computed = style->font_stretch.computed;
+        style_res->font_variant.value = style_res->font_variant.computed = style->font_variant.computed;
+    }
+
+    if (texts == 0 || !set)
+        return QUERY_STYLE_NOTHING;
+
+    if (texts > 1) {
+        if (different) {
+            return QUERY_STYLE_MULTIPLE_DIFFERENT;
+        } else {
+            return QUERY_STYLE_MULTIPLE_SAME;
+        }
+    } else {
+        return QUERY_STYLE_SINGLE;
+    }
+}
+
+/**
+ * Write to style_res the average font family of objects.
+ */
+int
+objects_query_fontfamily (GSList *objects, SPStyle *style_res)
+{
+    bool different = false;
+    int texts = 0;
+
+    if (style_res->text->font_family.value) {
+        g_free(style_res->text->font_family.value);
+        style_res->text->font_family.value = NULL;
+    }
+    style_res->text->font_family.set = FALSE;
+
+    for (GSList const *i = objects; i != NULL; i = i->next) {
+        SPObject *obj = SP_OBJECT (i->data);
+
+        if (!SP_IS_TEXT(obj) && !SP_IS_FLOWTEXT(obj)
+            && !SP_IS_TSPAN(obj) && !SP_IS_TEXTPATH(obj)
+            && !SP_IS_FLOWDIV(obj) && !SP_IS_FLOWPARA(obj) && !SP_IS_FLOWTSPAN(obj))
+            continue;
+
+        SPStyle *style = SP_OBJECT_STYLE (obj);
+        if (!style) continue;
+
+        texts ++;
+
+        if (style_res->text->font_family.value && style->text->font_family.value && 
+            strcmp (style_res->text->font_family.value, style->text->font_family.value)) {
+            different = true;  // different fonts
+        }
+
+        if (style_res->text->font_family.value) {
+            g_free(style_res->text->font_family.value);
+            style_res->text->font_family.value = NULL;
+        }
+
+        style_res->text->font_family.set = TRUE;
+        style_res->text->font_family.value = g_strdup(style->text->font_family.value);
+    }
+
+    if (texts == 0 || !style_res->text->font_family.set)
+        return QUERY_STYLE_NOTHING;
+
+    if (texts > 1) {
+        if (different) {
+            return QUERY_STYLE_MULTIPLE_DIFFERENT;
+        } else {
+            return QUERY_STYLE_MULTIPLE_SAME;
+        }
+    } else {
+        return QUERY_STYLE_SINGLE;
+    }
+}
+
+/**
+ * Query the given list of objects for the given property, write
+ * the result to style, return appropriate flag.
+ */
+int
+sp_desktop_query_style_from_list (GSList *list, SPStyle *style, int property)
+{
+    if (property == QUERY_STYLE_PROPERTY_FILL) {
+        return objects_query_fillstroke (list, style, true);
+    } else if (property == QUERY_STYLE_PROPERTY_STROKE) {
+        return objects_query_fillstroke (list, style, false);
+
+    } else if (property == QUERY_STYLE_PROPERTY_STROKEWIDTH) {
+        return objects_query_strokewidth (list, style);
+    } else if (property == QUERY_STYLE_PROPERTY_STROKEMITERLIMIT) {
+        return objects_query_miterlimit (list, style);
+    } else if (property == QUERY_STYLE_PROPERTY_STROKECAP) {
+        return objects_query_strokecap (list, style);
+    } else if (property == QUERY_STYLE_PROPERTY_STROKEJOIN) {
+        return objects_query_strokejoin (list, style);
+
+    } else if (property == QUERY_STYLE_PROPERTY_MASTEROPACITY) {
+        return objects_query_opacity (list, style);
+
+    } else if (property == QUERY_STYLE_PROPERTY_FONTFAMILY) {
+        return objects_query_fontfamily (list, style);
+    } else if (property == QUERY_STYLE_PROPERTY_FONTSTYLE) {
+        return objects_query_fontstyle (list, style);
+    } else if (property == QUERY_STYLE_PROPERTY_FONTNUMBERS) {
+        return objects_query_fontnumbers (list, style);
+    }
+
+    return QUERY_STYLE_NOTHING;
+}
+
+
+/**
+ * Query the subselection (if any) or selection on the given desktop for the given property, write
+ * the result to style, return appropriate flag.
+ */
+int
+sp_desktop_query_style(SPDesktop *desktop, SPStyle *style, int property)
+{
+    int ret = desktop->_query_style_signal.emit(style, property);
+
+    if (ret != QUERY_STYLE_NOTHING)  
+        return ret; // subselection returned a style, pass it on
+
+    // otherwise, do querying and averaging over selection
+    return sp_desktop_query_style_from_list ((GSList *) desktop->selection->itemList(), style, property);
+}
+
+/**
+ * Do the same as sp_desktop_query_style for all (defined) style properties, return true if none of
+ * the properties returned QUERY_STYLE_NOTHING.
+ */
+bool
+sp_desktop_query_style_all (SPDesktop *desktop, SPStyle *query)
+{
+        int result_family = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_FONTFAMILY);
+        int result_fstyle = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_FONTSTYLE); 
+        int result_fnumbers = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_FONTNUMBERS); 
+        int result_fill = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_FILL);
+        int result_stroke = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_STROKE);
+        int result_strokewidth = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_STROKEWIDTH);
+        int result_strokemiterlimit = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_STROKEMITERLIMIT);
+        int result_strokecap = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_STROKECAP);
+        int result_strokejoin = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_STROKEJOIN);
+        int result_opacity = sp_desktop_query_style (desktop, query, QUERY_STYLE_PROPERTY_MASTEROPACITY);
+
+        return (result_family != QUERY_STYLE_NOTHING && result_fstyle != QUERY_STYLE_NOTHING && result_fnumbers != QUERY_STYLE_NOTHING && result_fill != QUERY_STYLE_NOTHING && result_stroke != QUERY_STYLE_NOTHING && result_opacity != QUERY_STYLE_NOTHING && result_strokewidth != QUERY_STYLE_NOTHING && result_strokemiterlimit != QUERY_STYLE_NOTHING && result_strokecap != QUERY_STYLE_NOTHING && result_strokejoin != QUERY_STYLE_NOTHING);
+}
+
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :