merged SPColorSlider c++-sification from svgpaints branch

(bzr r14059.1.1)

4 files changed, 756 insertions, 0 deletions

diff --git a/src/ui/CMakeLists.txt b/src/ui/CMakeLists.txt
index 991d11feb..7ff0758e7 100644
--- a/src/ui/CMakeLists.txt
+++ b/src/ui/CMakeLists.txt
@@ -117,6 +117,7 @@ set(ui_SRC
 	widget/clipmaskicon.cpp
 	widget/color-picker.cpp
 	widget/color-preview.cpp
+	widget/color-slider.cpp
 	widget/dock-item.cpp
 	widget/dock.cpp
 	widget/entity-entry.cpp
@@ -289,6 +290,7 @@ set(ui_SRC
 	widget/button.h
 	widget/color-picker.h
 	widget/color-preview.h
+	widget/color-slider.h
 	widget/combo-enums.h
 	widget/dock-item.h
 	widget/dock.h
diff --git a/src/ui/widget/Makefile_insert b/src/ui/widget/Makefile_insert
index e18b790bd..34438a3ac 100644
--- a/src/ui/widget/Makefile_insert
+++ b/src/ui/widget/Makefile_insert
@@ -10,6 +10,8 @@ ink_common_sources +=	\
 	ui/widget/color-picker.h        \
 	ui/widget/color-preview.cpp     \
 	ui/widget/color-preview.h       \
+	ui/widget/color-slider.cpp      \
+	ui/widget/color-slider.h       \
 	ui/widget/combo-enums.h \
 	ui/widget/dock.h		\
 	ui/widget/dock.cpp		\
diff --git a/src/ui/widget/color-slider.cpp b/src/ui/widget/color-slider.cpp
new file mode 100644
index 000000000..fc64fad6f
--- /dev/null
+++ b/src/ui/widget/color-slider.cpp
@@ -0,0 +1,641 @@
+/**
+ * @file
+ * A slider with colored background - implementation.
+ */
+/* Author:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   bulia byak <buliabyak@users.sf.net>
+ *
+ * Copyright (C) 2001-2002 Lauris Kaplinski
+ *
+ * This code is in public domain
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include "color-slider.h"
+
+#include <gtk/gtk.h>
+#include <gdkmm/cursor.h>
+#include <gdkmm/screen.h>
+#include <gdkmm/general.h>
+#include <gtkmm/adjustment.h>
+#if GTK_CHECK_VERSION(3,0,0)
+#include <gtkmm/stylecontext.h>
+#else
+#include <gtkmm/style.h>
+#endif
+
+#include "widgets/sp-color-scales.h"
+#include "preferences.h"
+
+static const gint SLIDER_WIDTH = 96;
+static const gint SLIDER_HEIGHT = 8;
+static const gint ARROW_SIZE = 7;
+
+static const guchar *sp_color_slider_render_gradient (gint x0, gint y0, gint width, gint height,
+                              gint c[], gint dc[], guint b0, guint b1, guint mask);
+static const guchar *sp_color_slider_render_map (gint x0, gint y0, gint width, gint height,
+                         guchar *map, gint start, gint step, guint b0, guint b1, guint mask);
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+
+#if GTK_CHECK_VERSION(3,0,0)
+ColorSlider::ColorSlider(Glib::RefPtr<Gtk::Adjustment> adjustment)
+    : _dragging(false)
+#else
+ColorSlider::ColorSlider(Gtk::Adjustment* adjustment)
+    : _dragging(false)
+    , _adjustment(NULL)
+#endif
+    , _value(0.0)
+    , _oldvalue(0.0)
+    , _mapsize(0)
+    , _map(NULL)
+{
+    _c0[0] = 0x00;
+    _c0[1] = 0x00;
+    _c0[2] = 0x00;
+    _c0[3] = 0xff;
+
+    _cm[0] = 0xff;
+    _cm[1] = 0x00;
+    _cm[2] = 0x00;
+    _cm[3] = 0xff;
+
+    _c0[0] = 0xff;
+    _c0[1] = 0xff;
+    _c0[2] = 0xff;
+    _c0[3] = 0xff;
+
+    _b0 = 0x5f;
+    _b1 = 0xa0;
+    _bmask = 0x08;
+
+    set_adjustment(adjustment);
+}
+
+ColorSlider::~ColorSlider() {
+    if (_adjustment) {
+        _adjustment_changed_connection.disconnect();
+        _adjustment_value_changed_connection.disconnect();
+#if GTK_CHECK_VERSION(3,0,0)
+        _adjustment.reset();
+#else
+        _adjustment->unreference();
+        _adjustment = NULL;
+#endif
+    }
+}
+
+void ColorSlider::on_realize() {
+    set_realized();
+
+    if(!_refGdkWindow)
+    {
+      GdkWindowAttr attributes;
+      gint attributes_mask;
+      Gtk::Allocation allocation = get_allocation();
+
+      memset(&attributes, 0, sizeof(attributes));
+      attributes.x = allocation.get_x();
+      attributes.y = allocation.get_y();
+      attributes.width = allocation.get_width();
+      attributes.height = allocation.get_height();
+      attributes.window_type = GDK_WINDOW_CHILD;
+      attributes.wclass = GDK_INPUT_OUTPUT;
+      attributes.visual = gdk_screen_get_system_visual(gdk_screen_get_default());
+#if !GTK_CHECK_VERSION(3,0,0)
+      attributes.colormap = gdk_screen_get_system_colormap(gdk_screen_get_default());
+#endif
+      attributes.event_mask = get_events ();
+      attributes.event_mask |= (Gdk::EXPOSURE_MASK |
+                                Gdk::BUTTON_PRESS_MASK |
+                                Gdk::BUTTON_RELEASE_MASK |
+                                Gdk::POINTER_MOTION_MASK |
+                                Gdk::ENTER_NOTIFY_MASK |
+                                Gdk::LEAVE_NOTIFY_MASK);
+
+#if GTK_CHECK_VERSION(3,0,0)
+      attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL;
+#else
+      attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;
+#endif
+
+      _refGdkWindow = Gdk::Window::create(get_parent_window(), &attributes,
+              attributes_mask);
+      set_window(_refGdkWindow);
+      _refGdkWindow->set_user_data(gobj());
+
+#if !GTK_CHECK_VERSION(3,0,0)
+      style_attach();
+#endif
+    }
+}
+
+void ColorSlider::on_unrealize() {
+    _refGdkWindow.reset();
+
+    Gtk::Widget::on_unrealize();
+}
+
+void ColorSlider::on_size_allocate(Gtk::Allocation& allocation) {
+    set_allocation(allocation);
+
+    if (get_realized()) {
+        _refGdkWindow->move_resize(allocation.get_x(), allocation.get_y(),
+                allocation.get_width(), allocation.get_height());
+    }
+}
+
+#if GTK_CHECK_VERSION(3,0,0)
+
+void ColorSlider::get_preferred_width_vfunc(int& minimum_width, int& natural_width) const
+{
+    Glib::RefPtr<Gtk::StyleContext>style_context = get_style_context();
+    Gtk::Border padding = style_context->get_padding(get_state_flags());
+    int width = SLIDER_WIDTH + padding.get_left() + padding.get_right();
+    minimum_width = natural_width = width;
+}
+
+void ColorSlider::get_preferred_width_for_height_vfunc(int /*height*/, int& minimum_width, int& natural_width) const
+{
+    get_preferred_width(minimum_width, natural_width);
+}
+
+void ColorSlider::get_preferred_height_vfunc(int& minimum_height, int& natural_height) const
+{
+    Glib::RefPtr<Gtk::StyleContext>style_context = get_style_context();
+    Gtk::Border padding = style_context->get_padding(get_state_flags());
+    int height = SLIDER_HEIGHT + padding.get_top() + padding.get_bottom();
+    minimum_height = natural_height = height;
+}
+
+void ColorSlider::get_preferred_height_for_width_vfunc(int /*width*/, int& minimum_height, int& natural_height) const
+{
+    get_preferred_height(minimum_height, natural_height);
+}
+
+#else
+
+void ColorSlider::on_size_request(Gtk::Requisition* requisition) {
+    GtkStyle *style = gtk_widget_get_style(gobj());
+    requisition->width = SLIDER_WIDTH + style->xthickness * 2;
+    requisition->height = SLIDER_HEIGHT + style->ythickness * 2;
+}
+
+bool ColorSlider::on_expose_event(GdkEventExpose* event) {
+    bool result = false;
+
+    if (get_is_drawable()) {
+        Cairo::RefPtr<Cairo::Context> cr = _refGdkWindow->create_cairo_context();
+        result = on_draw(cr);
+    }
+    return result;
+}
+
+#endif
+
+bool ColorSlider::on_button_press_event(GdkEventButton *event) {
+    if (event->button == 1) {
+        Gtk::Allocation allocation = get_allocation();
+        gint cx, cw;
+#if GTK_CHECK_VERSION(3,0,0)
+        cx = get_style_context()->get_padding(get_state_flags()).get_left();
+#else
+        cx = get_style()->get_xthickness();
+#endif
+        cw = allocation.get_width() - 2 * cx;
+        signal_grabbed.emit();
+        _dragging = true;
+        _oldvalue = _value;
+        ColorScales::setScaled( _adjustment->gobj(), CLAMP ((gfloat) (event->x - cx) / cw, 0.0, 1.0) );
+        signal_dragged.emit();
+
+#if GTK_CHECK_VERSION(3,0,0)
+        gdk_device_grab(gdk_event_get_device(reinterpret_cast<GdkEvent *>(event)),
+                _refGdkWindow->gobj(),
+                GDK_OWNERSHIP_NONE,
+                FALSE,
+                static_cast<GdkEventMask>(GDK_POINTER_MOTION_MASK | GDK_BUTTON_RELEASE_MASK),
+                NULL,
+                event->time);
+#else
+        gdk_pointer_grab(get_window()->gobj(), FALSE,
+                static_cast<GdkEventMask>(GDK_POINTER_MOTION_MASK | GDK_BUTTON_RELEASE_MASK),
+                NULL, NULL, event->time);
+#endif
+    }
+
+    return false;
+}
+
+bool ColorSlider::on_button_release_event(GdkEventButton *event) {
+    if (event->button == 1) {
+
+#if GTK_CHECK_VERSION(3,0,0)
+        gdk_device_ungrab(gdk_event_get_device(reinterpret_cast<GdkEvent *>(event)),
+                                  gdk_event_get_time(reinterpret_cast<GdkEvent *>(event)));
+#else
+        get_window()->pointer_ungrab(event->time);
+#endif
+
+        _dragging = false;
+        signal_released.emit();
+        if (_value != _oldvalue) {
+            signal_value_changed.emit();
+        }
+    }
+
+    return false;
+}
+
+bool ColorSlider::on_motion_notify_event(GdkEventMotion *event) {
+    if (_dragging) {
+        gint cx, cw;
+        Gtk::Allocation allocation = get_allocation();
+#if GTK_CHECK_VERSION(3,0,0)
+        cx = get_style_context()->get_padding(get_state_flags()).get_left();
+#else
+        cx = get_style()->get_xthickness();
+#endif
+        cw = allocation.get_width() - 2 * cx;
+        ColorScales::setScaled( _adjustment->gobj(), CLAMP ((gfloat) (event->x - cx) / cw, 0.0, 1.0) );
+        signal_dragged.emit();
+    }
+
+    return false;
+}
+
+#if GTK_CHECK_VERSION(3,0,0)
+void ColorSlider::set_adjustment(Glib::RefPtr<Gtk::Adjustment> adjustment) {
+#else
+void ColorSlider::set_adjustment(Gtk::Adjustment *adjustment) {
+#endif
+    if (!adjustment) {
+#if GTK_CHECK_VERSION(3,0,0)
+        _adjustment = Gtk::Adjustment::create(0.0, 0.0, 1.0, 0.01, 0.0, 0.0);
+#else
+        _adjustment = Gtk::manage(new Gtk::Adjustment(0.0, 0.0, 1.0, 0.01, 0.0, 0.0));
+#endif
+    } else {
+        adjustment->set_page_increment(0.0);
+        adjustment->set_page_size(0.0);
+    }
+
+    if (_adjustment != adjustment) {
+        if (_adjustment) {
+            _adjustment_changed_connection.disconnect();
+            _adjustment_value_changed_connection.disconnect();
+#if !GTK_CHECK_VERSION(3,0,0)
+            _adjustment->unreference();
+#endif
+        }
+
+        _adjustment = adjustment;
+        _adjustment_changed_connection = _adjustment->signal_changed().connect(
+                sigc::mem_fun(this, &ColorSlider::_on_adjustment_changed));
+        _adjustment_value_changed_connection = _adjustment->signal_value_changed().connect(
+                sigc::mem_fun(this, &ColorSlider::_on_adjustment_value_changed));
+
+        _value = ColorScales::getScaled(_adjustment->gobj());
+
+        _on_adjustment_changed();
+    }
+}
+
+void ColorSlider::_on_adjustment_changed() {
+    queue_draw();
+}
+
+void ColorSlider::_on_adjustment_value_changed() {
+    if (_value != ColorScales::getScaled( _adjustment->gobj() )) {
+        gint cx, cy, cw, ch;
+#if GTK_CHECK_VERSION(3,0,0)
+        Glib::RefPtr<Gtk::StyleContext>style_context = get_style_context();
+        Gtk::Allocation allocation = get_allocation();
+        Gtk::Border padding = style_context->get_padding(get_state_flags());
+        cx = padding.get_left();
+        cy = padding.get_top();
+#else
+        Glib::RefPtr<Gtk::Style> style = get_style();
+        Gtk::Allocation allocation = get_allocation();
+        cx = style->get_xthickness();
+        cy = style->get_ythickness();
+#endif
+        cw = allocation.get_width() - 2 * cx;
+        ch = allocation.get_height() - 2 * cy;
+        if ((gint) (ColorScales::getScaled( _adjustment->gobj() ) * cw) != (gint) (_value * cw)) {
+            gint ax, ay;
+            gfloat value;
+            value = _value;
+            _value = ColorScales::getScaled( _adjustment->gobj() );
+            ax = (int)(cx + value * cw - ARROW_SIZE / 2 - 2);
+            ay = cy;
+            queue_draw_area(ax, ay, ARROW_SIZE + 4, ch);
+            ax = (int)(cx + _value * cw - ARROW_SIZE / 2 - 2);
+            ay = cy;
+            queue_draw_area(ax, ay, ARROW_SIZE + 4, ch);
+        } else {
+            _value = ColorScales::getScaled( _adjustment->gobj() );
+        }
+    }
+}
+
+void ColorSlider::set_colors(guint32 start, guint32 mid, guint32 end) {
+    // Remove any map, if set
+    _map = 0;
+
+    _c0[0] = start >> 24;
+    _c0[1] = (start >> 16) & 0xff;
+    _c0[2] = (start >> 8) & 0xff;
+    _c0[3] = start & 0xff;
+
+    _cm[0] = mid >> 24;
+    _cm[1] = (mid >> 16) & 0xff;
+    _cm[2] = (mid >> 8) & 0xff;
+    _cm[3] = mid & 0xff;
+
+    _c1[0] = end >> 24;
+    _c1[1] = (end >> 16) & 0xff;
+    _c1[2] = (end >> 8) & 0xff;
+    _c1[3] = end & 0xff;
+
+    queue_draw();
+}
+
+void ColorSlider::set_map(const guchar *map) {
+    _map = const_cast<guchar *>(map);
+
+    queue_draw();
+}
+
+void ColorSlider::set_background(guint dark, guint light, guint size) {
+    _b0 = dark;
+    _b1 = light;
+    _bmask = size;
+
+    queue_draw();
+}
+
+bool ColorSlider::on_draw(const Cairo::RefPtr<Cairo::Context>& cr) {
+    gboolean colorsOnTop = Inkscape::Preferences::get()->getBool("/options/workarounds/colorsontop", false);
+
+    Gtk::Allocation allocation = get_allocation();
+
+#if GTK_CHECK_VERSION(3,0,0)
+    Glib::RefPtr<Gtk::StyleContext> style_context = get_style_context();
+#else
+    Glib::RefPtr<Gdk::Window> window = get_window();
+    Glib::RefPtr<Gtk::Style> style = get_style();
+#endif
+
+    // Draw shadow
+    if (colorsOnTop) {
+#if GTK_CHECK_VERSION(3,0,0)
+        style_context->render_frame(cr, 0, 0,
+                allocation.get_width(), allocation.get_height());
+#else
+        gtk_paint_shadow( style->gobj(), window->gobj(),
+                  gtk_widget_get_state(gobj()), GTK_SHADOW_IN,
+                  NULL, gobj(), "colorslider",
+                  0, 0,
+                  allocation.get_width(), allocation.get_height());
+#endif
+    }
+
+    /* Paintable part of color gradient area */
+    Gdk::Rectangle carea;
+
+#if GTK_CHECK_VERSION(3,0,0)
+    Gtk::Border padding;
+
+    padding = style_context->get_padding(get_state_flags());
+
+    carea.set_x(padding.get_left());
+    carea.set_y(padding.get_top());;
+#else
+    carea.set_x(style->get_xthickness());
+    carea.set_y(style->get_ythickness());
+#endif
+
+    carea.set_width(allocation.get_width() - 2 * carea.get_x());
+    carea.set_height(allocation.get_height() - 2 * carea.get_y());
+
+    if (_map) {
+        /* Render map pixelstore */
+        gint d = (1024 << 16) / carea.get_width();
+        gint s = 0;
+
+        const guchar *b = sp_color_slider_render_map(0, 0, carea.get_width(), carea.get_height(),
+                                                             _map, s, d,
+                                                             _b0, _b1, _bmask);
+
+        if (b != NULL && carea.get_width() > 0) {
+            Glib::RefPtr<Gdk::Pixbuf> pb = Gdk::Pixbuf::create_from_data(b, Gdk::COLORSPACE_RGB,
+                    false, 8, carea.get_width(), carea.get_height(), carea.get_width() * 3);
+
+            Gdk::Cairo::set_source_pixbuf(cr, pb, carea.get_x(), carea.get_y());
+            cr->paint();
+        }
+
+    } else {
+        gint c[4], dc[4];
+
+        /* Render gradient */
+
+        // part 1: from c0 to cm
+        if (carea.get_width() > 0) {
+            for (gint i = 0; i < 4; i++) {
+                c[i] = _c0[i] << 16;
+                dc[i] = ((_cm[i] << 16) - c[i]) / (carea.get_width()/2);
+            }
+            guint wi = carea.get_width()/2;
+            const guchar *b = sp_color_slider_render_gradient(0, 0, wi, carea.get_height(),
+                                                                          c, dc, _b0, _b1, _bmask);
+
+            /* Draw pixelstore 1 */
+            if (b != NULL && wi > 0) {
+                Glib::RefPtr<Gdk::Pixbuf> pb = Gdk::Pixbuf::create_from_data(b, Gdk::COLORSPACE_RGB,
+                        false, 8, wi, carea.get_height(), wi * 3);
+
+                Gdk::Cairo::set_source_pixbuf(cr, pb, carea.get_x(), carea.get_y());
+                cr->paint();
+            }
+        }
+
+        // part 2: from cm to c1
+        if (carea.get_width() > 0) {
+            for (gint i = 0; i < 4; i++) {
+                c[i] = _cm[i] << 16;
+                dc[i] = ((_c1[i] << 16) - c[i]) / (carea.get_width()/2);
+            }
+            guint wi = carea.get_width()/2;
+            const guchar *b = sp_color_slider_render_gradient(carea.get_width()/2, 0, wi, carea.get_height(),
+                                                      c, dc,
+                                                                          _b0, _b1, _bmask);
+
+            /* Draw pixelstore 2 */
+            if (b != NULL && wi > 0) {
+                Glib::RefPtr<Gdk::Pixbuf> pb = Gdk::Pixbuf::create_from_data(b, Gdk::COLORSPACE_RGB,
+                        false, 8, wi, carea.get_height(), wi * 3);
+
+                Gdk::Cairo::set_source_pixbuf(cr, pb,  carea.get_width()/2 + carea.get_x(), carea.get_y());
+                cr->paint();
+            }
+        }
+    }
+
+        /* Draw shadow */
+        if (!colorsOnTop) {
+#if GTK_CHECK_VERSION(3,0,0)
+            style_context->render_frame(cr, 0, 0,
+                    allocation.get_width(), allocation.get_height());
+#else
+            gtk_paint_shadow( style->gobj(), window->gobj(),
+                      gtk_widget_get_state(gobj()), GTK_SHADOW_IN,
+                      NULL, gobj(), "colorslider",
+                      0, 0,
+                      allocation.get_width(), allocation.get_height());
+#endif
+        }
+
+    /* Draw arrow */
+    gint x = (int)(_value * (carea.get_width() - 1) - ARROW_SIZE / 2 + carea.get_x());
+    gint y1 = carea.get_y();
+    gint y2 = carea.get_y() + carea.get_height() - 1;
+    cr->set_line_width(1.0);
+
+    // Define top arrow
+    cr->move_to(x - 0.5,                y1 + 0.5);
+    cr->line_to(x + ARROW_SIZE - 0.5,   y1 + 0.5);
+    cr->line_to(x + (ARROW_SIZE-1)/2.0, y1 + ARROW_SIZE/2.0 + 0.5);
+    cr->line_to(x - 0.5,                y1 + 0.5);
+
+    // Define bottom arrow
+    cr->move_to(x - 0.5,                y2 + 0.5);
+    cr->line_to(x + ARROW_SIZE - 0.5,   y2 + 0.5);
+    cr->line_to(x + (ARROW_SIZE-1)/2.0, y2 - ARROW_SIZE/2.0 + 0.5);
+    cr->line_to(x - 0.5,                y2 + 0.5);
+
+    // Render both arrows
+    cr->set_source_rgb(1.0, 1.0, 1.0);
+    cr->stroke_preserve();
+    cr->set_source_rgb(0.0, 0.0, 0.0);
+    cr->fill();
+
+    return false;
+}
+
+}//namespace Widget
+}//namespace UI
+}//namespace Inkscape
+
+/* Colors are << 16 */
+
+static const guchar *
+sp_color_slider_render_gradient (gint x0, gint y0, gint width, gint height,
+				 gint c[], gint dc[], guint b0, guint b1, guint mask)
+{
+	static guchar *buf = NULL;
+	static gint bs = 0;
+	guchar *dp;
+	gint x, y;
+	guint r, g, b, a;
+
+	if (buf && (bs < width * height)) {
+		g_free (buf);
+		buf = NULL;
+	}
+	if (!buf) {
+		buf = g_new (guchar, width * height * 3);
+		bs = width * height;
+	}
+
+	dp = buf;
+	r = c[0];
+	g = c[1];
+	b = c[2];
+	a = c[3];
+	for (x = x0; x < x0 + width; x++) {
+		gint cr, cg, cb, ca;
+		guchar *d;
+		cr = r >> 16;
+		cg = g >> 16;
+		cb = b >> 16;
+		ca = a >> 16;
+		d = dp;
+		for (y = y0; y < y0 + height; y++) {
+			guint bg, fc;
+			/* Background value */
+			bg = ((x & mask) ^ (y & mask)) ? b0 : b1;
+			fc = (cr - bg) * ca;
+			d[0] = bg + ((fc + (fc >> 8) + 0x80) >> 8);
+			fc = (cg - bg) * ca;
+			d[1] = bg + ((fc + (fc >> 8) + 0x80) >> 8);
+			fc = (cb - bg) * ca;
+			d[2] = bg + ((fc + (fc >> 8) + 0x80) >> 8);
+			d += 3 * width;
+		}
+		r += dc[0];
+		g += dc[1];
+		b += dc[2];
+		a += dc[3];
+		dp += 3;
+	}
+
+	return buf;
+}
+
+/* Positions are << 16 */
+
+static const guchar *
+sp_color_slider_render_map (gint x0, gint y0, gint width, gint height,
+			    guchar *map, gint start, gint step, guint b0, guint b1, guint mask)
+{
+	static guchar *buf = NULL;
+	static gint bs = 0;
+	guchar *dp;
+	gint x, y;
+
+	if (buf && (bs < width * height)) {
+		g_free (buf);
+		buf = NULL;
+	}
+	if (!buf) {
+		buf = g_new (guchar, width * height * 3);
+		bs = width * height;
+	}
+
+	dp = buf;
+	for (x = x0; x < x0 + width; x++) {
+		gint cr, cg, cb, ca;
+		guchar *d = dp;
+		guchar *sp = map + 4 * (start >> 16);
+		cr = *sp++;
+		cg = *sp++;
+		cb = *sp++;
+		ca = *sp++;
+		for (y = y0; y < y0 + height; y++) {
+			guint bg, fc;
+			/* Background value */
+			bg = ((x & mask) ^ (y & mask)) ? b0 : b1;
+			fc = (cr - bg) * ca;
+			d[0] = bg + ((fc + (fc >> 8) + 0x80) >> 8);
+			fc = (cg - bg) * ca;
+			d[1] = bg + ((fc + (fc >> 8) + 0x80) >> 8);
+			fc = (cb - bg) * ca;
+			d[2] = bg + ((fc + (fc >> 8) + 0x80) >> 8);
+			d += 3 * width;
+		}
+		dp += 3;
+		start += step;
+	}
+
+	return buf;
+}
+
diff --git a/src/ui/widget/color-slider.h b/src/ui/widget/color-slider.h
new file mode 100644
index 000000000..00cc17ea7
--- /dev/null
+++ b/src/ui/widget/color-slider.h
@@ -0,0 +1,111 @@
+#ifndef __SP_COLOR_SLIDER_H__
+#define __SP_COLOR_SLIDER_H__
+
+/*
+ * A slider with colored background
+ *
+ * Author:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *
+ * Copyright (C) 2001-2002 Lauris Kaplinski
+ *
+ * This code is in public domain
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#if GLIBMM_DISABLE_DEPRECATED && HAVE_GLIBMM_THREADS_H
+#include <glibmm/threads.h>
+#endif
+
+#include <gtkmm/widget.h>
+#include <sigc++/signal.h>
+
+namespace Inkscape
+{
+namespace UI
+{
+namespace Widget
+{
+
+/*
+ * A slider with colored background
+ */
+class ColorSlider: public Gtk::Widget {
+public:
+#if GTK_CHECK_VERSION(3,0,0)
+    ColorSlider(Glib::RefPtr<Gtk::Adjustment> adjustment);
+#else
+    ColorSlider(Gtk::Adjustment *adjustment);
+#endif
+    ~ColorSlider();
+
+#if GTK_CHECK_VERSION(3,0,0)
+    void set_adjustment(Glib::RefPtr<Gtk::Adjustment> adjustment);
+#else
+    void set_adjustment(Gtk::Adjustment *adjustment);
+#endif
+
+    void set_colors(guint32 start, guint32 mid, guint32 end);
+
+    void set_map(const guchar* map);
+
+    void set_background(guint dark, guint light, guint size);
+
+    sigc::signal<void> signal_grabbed;
+    sigc::signal<void> signal_dragged;
+    sigc::signal<void> signal_released;
+    sigc::signal<void> signal_value_changed;
+
+protected:
+    void on_size_allocate(Gtk::Allocation& allocation);
+    void on_realize();
+    void on_unrealize();
+    bool on_button_press_event(GdkEventButton *event);
+    bool on_button_release_event(GdkEventButton *event);
+    bool on_motion_notify_event(GdkEventMotion *event);
+    bool on_draw(const Cairo::RefPtr<Cairo::Context>& cr);
+
+#if GTK_CHECK_VERSION(3,0,0)
+    void get_preferred_width_vfunc(int& minimum_width, int& natural_width) const;
+    void get_preferred_width_for_height_vfunc(int height, int& minimum_width, int& natural_width) const;
+    void get_preferred_height_vfunc(int& minimum_height, int& natural_height) const;
+    void get_preferred_height_for_width_vfunc(int width, int& minimum_height, int& natural_height) const;
+#else
+    void on_size_request(Gtk::Requisition* requisition);
+    bool on_expose_event(GdkEventExpose* event);
+#endif
+
+private:
+    void _on_adjustment_changed();
+    void _on_adjustment_value_changed();
+
+    bool _dragging;
+
+#if GTK_CHECK_VERSION(3,0,0)
+    Glib::RefPtr<Gtk::Adjustment> _adjustment;
+#else
+    Gtk::Adjustment *_adjustment;
+#endif
+    sigc::connection _adjustment_changed_connection;
+    sigc::connection _adjustment_value_changed_connection;
+
+    gfloat _value;
+    gfloat _oldvalue;
+    guchar _c0[4], _cm[4], _c1[4];
+    guchar _b0, _b1;
+    guchar _bmask;
+
+    gint _mapsize;
+    guchar *_map;
+
+    Glib::RefPtr<Gdk::Window> _refGdkWindow;
+};
+
+}//namespace Widget
+}//namespace UI
+}//namespace Inkscape
+
+#endif