// SPDX-License-Identifier: GPL-2.0-or-later /* * Color wheel widget. Outer ring for Hue. Inner triangle for Saturation and Value. * * Copyright (C) 2018 Tavmjong Bah * * The contents of this file may be used under the GNU General Public License Version 2 or later. * */ #include "ink-color-wheel.h" // A point with a color value. class color_point { public: color_point() : x(0), y(0), r(0), g(0), b(0) {}; color_point(double x, double y, double r, double g, double b) : x(x), y(y), r(r), g(g), b(b) {}; color_point(double x, double y, guint32 color) : x(x), y(y), r(((color & 0xff0000) >> 16)/255.0), g(((color & 0xff00) >> 8)/255.0), b(((color & 0xff) )/255.0) {}; guint32 get_color() { return (int(r*255) << 16 | int(g*255) << 8 | int(b*255)); }; double x; double y; double r; double g; double b; }; inline double lerp(const double& v0, const double& v1, const double& t0, const double&t1, const double& t) { double s = 0; if (t0 != t1) { s = (t - t0)/(t1 - t0); } return (1.0 - s) * v0 + s * v1; } inline color_point lerp(const color_point& v0, const color_point& v1, const double &t0, const double &t1, const double& t) { double x = lerp(v0.x, v1.x, t0, t1, t); double y = lerp(v0.y, v1.y, t0, t1, t); double r = lerp(v0.r, v1.r, t0, t1, t); double g = lerp(v0.g, v1.g, t0, t1, t); double b = lerp(v0.b, v1.b, t0, t1, t); return (color_point(x, y, r, g, b)); } inline double clamp(const double& value, const double& min, const double& max) { if (value < min) return min; if (value > max) return max; return value; } // h, s, and v in range 0 to 1. Returns rgb value useful for use in Cairo. guint32 hsv_to_rgb(double h, double s, double v) { if (h < 0.0 || h > 1.0 || s < 0.0 || s > 1.0 || v < 0.0 || v > 1.0) { std::cerr << "ColorWheel: hsv_to_rgb: input out of bounds: (0-1)" << " h: " << h << " s: " << s << " v: " << v << std::endl; return 0x0; } double r = v; double g = v; double b = v; if (s != 0.0) { double c = s * v; if (h == 1.0) h = 0.0; h *= 6.0; double f = h - (int)h; double p = v * (1.0 - s); double q = v * (1.0 - s * f); double t = v * (1.0 - s * (1.0 - f)); switch ((int)h) { case 0: r = v; g = t; b = p; break; case 1: r = q; g = v; b = p; break; case 2: r = p; g = v; b = t; break; case 3: r = p; g = q; b = v; break; case 4: r = t; g = p; b = v; break; case 5: r = v; g = p; b = q; break; default: g_assert_not_reached(); } } guint32 rgb = (((int)floor (r*255 + 0.5) << 16) | ((int)floor (g*255 + 0.5) << 8) | ((int)floor (b*255 + 0.5) )); return rgb; } double luminance(guint32 color) { double r(((color & 0xff0000) >> 16)/255.0); double g(((color & 0xff00) >> 8)/255.0); double b(((color & 0xff) )/255.0); return (r * 0.2125 + g * 0.7154 + b * 0.0721); } namespace Inkscape { namespace UI { namespace Widget { ColorWheel::ColorWheel() : _hue(0.0) , _saturation(1.0) , _value(1.0) , _ring_width(0.2) , _mode(DRAG_NONE) , _focus_on_ring(true) { set_name("ColorWheel"); add_events(Gdk::BUTTON_PRESS_MASK | Gdk::BUTTON_RELEASE_MASK | Gdk::BUTTON_MOTION_MASK | Gdk::KEY_PRESS_MASK ); set_can_focus(); } void ColorWheel::set_rgb(const double& r, const double&g, const double&b, bool override_hue) { double Min = std::min({r, g, b}); double Max = std::max({r, g, b}); _value = Max; if (Min == Max) { if (override_hue) { _hue = 0.0; } } else { if (Max == r) { _hue = ((g-b)/(Max-Min) )/6.0; } else if (Max == g) { _hue = ((b-r)/(Max-Min) + 2)/6.0; } else { _hue = ((r-g)/(Max-Min) + 4)/6.0; } if (_hue < 0.0) { _hue += 1.0; } } if (Max == 0) { _saturation = 0; } else { _saturation = (Max - Min)/Max; } } void ColorWheel::get_rgb(double& r, double& g, double& b) { guint32 color = get_rgb(); r = ((color & 0xff0000) >> 16)/255.0; g = ((color & 0x00ff00) >> 8)/255.0; b = ((color & 0x0000ff) )/255.0; } guint32 ColorWheel::get_rgb() { return hsv_to_rgb(_hue, _saturation, _value); } /* Pad triangle vertically if necessary */ void draw_vertical_padding(color_point p0, color_point p1, int padding, bool pad_upwards, guint32 *buffer, int height, int stride); bool ColorWheel::on_draw(const::Cairo::RefPtr<::Cairo::Context>& cr) { Gtk::Allocation allocation = get_allocation(); const int width = allocation.get_width(); const int height = allocation.get_height(); const int stride = Cairo::ImageSurface::format_stride_for_width(Cairo::FORMAT_RGB24, width); int cx = width/2; int cy = height/2; int focus_line_width; int focus_padding; get_style_property("focus-line-width", focus_line_width); get_style_property("focus-padding", focus_padding); // Paint ring guint32* buffer_ring = g_new (guint32, height * stride / 4); double r_max = std::min( width, height)/2.0 - 2 * (focus_line_width + focus_padding); double r_min = r_max * (1.0 - _ring_width); double r2_max = (r_max+1) * (r_max+1); // Must expand a bit to avoid edge effects. double r2_min = (r_min-1) * (r_min-1); // Must shrink a bit to avoid edge effects. for (int i = 0; i < height; ++i) { guint32* p = buffer_ring + i * width; double dy = (cy - i); for (int j = 0; j < width; ++j) { double dx = (j - cx); double r2 = dx * dx + dy * dy; if (r2 < r2_min || r2 > r2_max) { *p++ = 0; // Save calculation time. } else { double angle = atan2 (dy, dx); if (angle < 0.0) { angle += 2.0 * M_PI; } double hue = angle/(2.0 * M_PI); *p++ = hsv_to_rgb(hue, 1.0, 1.0); } } } Cairo::RefPtr<::Cairo::ImageSurface> source_ring = ::Cairo::ImageSurface::create((unsigned char *)buffer_ring, Cairo::FORMAT_RGB24, width, height, stride); cr->set_antialias(Cairo::ANTIALIAS_SUBPIXEL); // Paint line on ring in source (so it gets clipped by stroke). double l = 0.0; guint32 color_on_ring = hsv_to_rgb(_hue, 1.0, 1.0); if (luminance(color_on_ring) < 0.5) l = 1.0; Cairo::RefPtr<::Cairo::Context> cr_source_ring = ::Cairo::Context::create(source_ring); cr_source_ring->set_source_rgb(l, l, l); cr_source_ring->move_to (cx, cy); cr_source_ring->line_to (cx + cos(_hue * M_PI * 2.0) * r_max+1, cy - sin(_hue * M_PI * 2.0) * r_max+1); cr_source_ring->stroke(); // Paint with ring surface, clipping to ring. cr->save(); cr->set_source(source_ring, 0, 0); cr->set_line_width (r_max - r_min); cr->begin_new_path(); cr->arc(cx, cy, (r_max + r_min)/2.0, 0, 2.0 * M_PI); cr->stroke(); cr->restore(); g_free(buffer_ring); // Draw focus if (has_focus() && _focus_on_ring) { Glib::RefPtr style_context = get_style_context(); style_context->render_focus(cr, 0, 0, width, height); } // Paint triangle. /* The triangle is painted by first finding color points on the * edges of the triangle at the same y value via linearly * interpolating between corner values, and then interpolating along * x between the those edge points. The interpolation is in sRGB * space which leads to a complicated mapping between x/y and * saturation/value. This was probably done to remove the need to * convert between HSV and RGB for each pixel. * Black corner: v = 0, s = 1 * White corner: v = 1, s = 0 * Color corner; v = 1, s = 1 */ const int padding = 3; // Avoid edge artifacts. double x0, y0, x1, y1, x2, y2; triangle_corners(x0, y0, x1, y1, x2, y2); guint32 color0 = hsv_to_rgb(_hue, 1.0, 1.0); guint32 color1 = hsv_to_rgb(_hue, 1.0, 0.0); guint32 color2 = hsv_to_rgb(_hue, 0.0, 1.0); color_point p0 (x0, y0, color0); color_point p1 (x1, y1, color1); color_point p2 (x2, y2, color2); // Reorder so we paint from top down. if (p1.y > p2.y) { std::swap(p1, p2); } if (p0.y > p2.y) { std::swap(p0, p2); } if (p0.y > p1.y) { std::swap(p0, p1); } guint32* buffer_triangle = g_new (guint32, height * stride / 4); for (int y = 0; y < height; ++y) { guint32 *p = buffer_triangle + y * (stride / 4); if (p0.y <= y+padding && y-padding < p2.y) { // Get values on side at position y. color_point side0; double y_inter = clamp(y, p0.y, p2.y); if (y < p1.y) { side0 = lerp(p0, p1, p0.y, p1.y, y_inter); } else { side0 = lerp(p1, p2, p1.y, p2.y, y_inter); } color_point side1 = lerp(p0, p2, p0.y, p2.y, y_inter); // side0 should be on left if (side0.x > side1.x) { std::swap (side0, side1); } int x_start = std::max(0, int(side0.x)); int x_end = std::min(int(side1.x), width); for (int x = 0; x < width; ++x) { if (x <= x_start) { *p++ = side0.get_color(); } else if (x < x_end) { *p++ = lerp(side0, side1, side0.x, side1.x, x).get_color(); } else { *p++ = side1.get_color(); } } } } // add vertical padding to each side separately color_point temp_point = lerp(p0, p1, p0.x, p1.x, (p0.x + p1.x) / 2.0); bool pad_upwards = is_in_triangle(temp_point.x, temp_point.y + 1); draw_vertical_padding(p0, p1, padding, pad_upwards, buffer_triangle, height, stride / 4); temp_point = lerp(p0, p2, p0.x, p2.x, (p0.x + p2.x) / 2.0); pad_upwards = is_in_triangle(temp_point.x, temp_point.y + 1); draw_vertical_padding(p0, p2, padding, pad_upwards, buffer_triangle, height, stride / 4); temp_point = lerp(p1, p2, p1.x, p2.x, (p1.x + p2.x) / 2.0); pad_upwards = is_in_triangle(temp_point.x, temp_point.y + 1); draw_vertical_padding(p1, p2, padding, pad_upwards, buffer_triangle, height, stride / 4); Cairo::RefPtr<::Cairo::ImageSurface> source_triangle = ::Cairo::ImageSurface::create((unsigned char *)buffer_triangle, Cairo::FORMAT_RGB24, width, height, stride); // Paint with triangle surface, clipping to triangle. cr->save(); cr->set_source(source_triangle, 0, 0); cr->move_to(p0.x, p0.y); cr->line_to(p1.x, p1.y); cr->line_to(p2.x, p2.y); cr->close_path(); cr->fill(); cr->restore(); g_free(buffer_triangle); // Draw marker double mx = x1 + (x2-x1) * _value + (x0-x2) * _saturation * _value; double my = y1 + (y2-y1) * _value + (y0-y2) * _saturation * _value; double a = 0.0; guint32 color_at_marker = get_rgb(); if (luminance(color_at_marker) < 0.5) a = 1.0; cr->set_source_rgb(a, a, a); cr->begin_new_path(); cr->arc(mx, my, 4, 0, 2 * M_PI); cr->stroke(); // Draw focus if (has_focus() && !_focus_on_ring) { Glib::RefPtr style_context = get_style_context(); style_context->render_focus(cr, mx-4, my-4, 8, 8); // This doesn't seem to work. cr->set_line_width(0.5); cr->set_source_rgb(1-a, 1-a, 1-a); cr->begin_new_path(); cr->arc(mx, my, 7, 0, 2 * M_PI); cr->stroke(); } return true; } void draw_vertical_padding(color_point p0, color_point p1, int padding, bool pad_upwards, guint32 *buffer, int height, int stride) { // skip if horizontal padding is more accurate double gradient = (p1.y - p0.y) / (p1.x - p0.x); if (std::abs(gradient) > 1.0) { return; } double min_y = std::min(p0.y, p1.y); double max_y = std::max(p0.y, p1.y); double min_x = std::min(p0.x, p1.x); double max_x = std::max(p0.x, p1.x); for (int y = min_y; y <= max_y; ++y) { double start_x = lerp(p0, p1, p0.y, p1.y, clamp(y, min_y, max_y)).x; double end_x = lerp(p0, p1, p0.y, p1.y, clamp(y + 1, min_y, max_y)).x; if (start_x > end_x) { std::swap(start_x, end_x); } guint32 *p = buffer + y * stride; p += static_cast(start_x); for (int x = start_x; x <= end_x; ++x) { color_point point = lerp(p0, p1, p0.x, p1.x, clamp(x, min_x, max_x)); for (int offset = 0; offset <= padding; ++offset) { if (pad_upwards && (point.y - offset) >= 0) { *(p - (offset * stride)) = point.get_color(); } else if (!pad_upwards && (point.y + offset) < height) { *(p + (offset * stride)) = point.get_color(); } } ++p; } } } // Find triangle corners given hue and radius. void ColorWheel::triangle_corners(double &x0, double &y0, double &x1, double &y1, double &x2, double &y2) { Gtk::Allocation allocation = get_allocation(); const int width = allocation.get_width(); const int height = allocation.get_height(); int cx = width/2; int cy = height/2; int focus_line_width; int focus_padding; get_style_property("focus-line-width", focus_line_width); get_style_property("focus-padding", focus_padding); double r_max = std::min( width, height)/2.0 - 2 * (focus_line_width + focus_padding); double r_min = r_max * (1.0 - _ring_width); double angle = _hue * 2.0 * M_PI; x0 = cx + cos(angle) * r_min; y0 = cy - sin(angle) * r_min; x1 = cx + cos(angle + 2.0 * M_PI / 3.0) * r_min; y1 = cy - sin(angle + 2.0 * M_PI / 3.0) * r_min; x2 = cx + cos(angle + 4.0 * M_PI / 3.0) * r_min; y2 = cy - sin(angle + 4.0 * M_PI / 3.0) * r_min; } void ColorWheel::set_from_xy(const double& x, const double& y) { Gtk::Allocation allocation = get_allocation(); const int width = allocation.get_width(); const int height = allocation.get_height(); double cx = width/2.0; double cy = height/2.0; double r = std::min(cx, cy) * (1 - _ring_width); // We calculate RGB value under the cursor by rotating the cursor // and triangle by the hue value and looking at position in the // now right pointing triangle. double angle = _hue * 2 * M_PI; double Sin = sin(angle); double Cos = cos(angle); double xp = ((x-cx) * Cos - (y-cy) * Sin) / r; double yp = ((x-cx) * Sin + (y-cy) * Cos) / r; double xt = lerp(0.0, 1.0, -0.5, 1.0, xp); xt = clamp(xt, 0, 1); double dy = (1-xt) * cos(M_PI/6.0); double yt = lerp(0.0, 1.0, -dy, dy, yp); yt = clamp(yt, 0, 1); color_point c0(0, 0, yt, yt, yt); // Grey point along base. color_point c1(0, 0, hsv_to_rgb(_hue, 1, 1)); // Hue point at apex color_point c = lerp(c0, c1, 0, 1, xt); set_rgb(c.r, c.g, c.b, false); // Don't override previous hue. } bool ColorWheel::is_in_ring(const double& x, const double& y) { Gtk::Allocation allocation = get_allocation(); const int width = allocation.get_width(); const int height = allocation.get_height(); int cx = width/2; int cy = height/2; int focus_line_width; int focus_padding; get_style_property("focus-line-width", focus_line_width); get_style_property("focus-padding", focus_padding); double r_max = std::min( width, height)/2.0 - 2 * (focus_line_width + focus_padding); double r_min = r_max * (1.0 - _ring_width); double r2_max = r_max * r_max; double r2_min = r_min * r_min; double dx = x - cx; double dy = y - cy; double r2 = dx * dx + dy * dy; return (r2_min < r2 && r2 < r2_max); } bool ColorWheel::is_in_triangle(const double& x, const double& y) { double x0, y0, x1, y1, x2, y2; triangle_corners(x0, y0, x1, y1, x2, y2); double det = (x2-x1) * (y0-y1) - (y2-y1) * (x0-x1); double s = ((x -x1) * (y0-y1) - (y -y1) * (x0-x1)) / det; double t = ((x2-x1) * (y -y1) - (y2-y1) * (x -x1)) / det; return (s >= 0.0 && t >= 0.0 && s+t <= 1.0); } bool ColorWheel::on_focus(Gtk::DirectionType direction) { // In forward direction, focus passes from no focus to ring focus to triangle focus to no focus. if (!has_focus()) { _focus_on_ring = (direction == Gtk::DIR_TAB_FORWARD); grab_focus(); return true; } // Already have focus bool keep_focus = false; switch (direction) { case Gtk::DIR_UP: case Gtk::DIR_LEFT: case Gtk::DIR_TAB_BACKWARD: if (!_focus_on_ring) { _focus_on_ring = true; keep_focus = true; } break; case Gtk::DIR_DOWN: case Gtk::DIR_RIGHT: case Gtk::DIR_TAB_FORWARD: if (_focus_on_ring) { _focus_on_ring = false; keep_focus = true; } break; } queue_draw(); // Update focus indicators. return keep_focus; } bool ColorWheel::on_button_press_event(GdkEventButton* event) { // Seat is automatically grabbed. double x = event->x; double y = event->y; if (is_in_ring(x, y) ) { _mode = DRAG_H; grab_focus(); _focus_on_ring = true; return true; } if (is_in_triangle(x, y)) { _mode = DRAG_SV; grab_focus(); _focus_on_ring = false; return true; } return false; } bool ColorWheel::on_button_release_event(GdkEventButton* event) { _mode = DRAG_NONE; return true; } bool ColorWheel::on_motion_notify_event(GdkEventMotion* event) { double x = event->x; double y = event->y; Gtk::Allocation allocation = get_allocation(); const int width = allocation.get_width(); const int height = allocation.get_height(); double cx = width/2.0; double cy = height/2.0; double r = std::min(cx, cy) * (1 - _ring_width); if (_mode == DRAG_H) { double angle = -atan2(y-cy, x-cx); if (angle < 0) angle += 2.0 * M_PI; _hue = angle / (2.0 * M_PI); queue_draw(); _signal_color_changed.emit(); return true; } if (_mode == DRAG_SV) { set_from_xy(x, y); _signal_color_changed.emit(); queue_draw(); return true; } return false; } bool ColorWheel::on_key_press_event(GdkEventKey* key_event) { bool consumed = false; unsigned int key = 0; gdk_keymap_translate_keyboard_state( Gdk::Display::get_default()->get_keymap(), key_event->hardware_keycode, (GdkModifierType)key_event->state, 0, &key, nullptr, nullptr, nullptr ); double x0, y0, x1, y1, x2, y2; triangle_corners(x0, y0, x1, y1, x2, y2); // Marker position double mx = x1 + (x2-x1) * _value + (x0-x2) * _saturation * _value; double my = y1 + (y2-y1) * _value + (y0-y2) * _saturation * _value; const double delta_hue = 2.0/360.0; switch (key) { case GDK_KEY_Up: case GDK_KEY_KP_Up: if (_focus_on_ring) { _hue += delta_hue; } else { my -= 1.0; set_from_xy(mx, my); } consumed = true; break; case GDK_KEY_Down: case GDK_KEY_KP_Down: if (_focus_on_ring) { _hue -= delta_hue; } else { my += 1.0; set_from_xy(mx, my); } consumed = true; break; case GDK_KEY_Left: case GDK_KEY_KP_Left: if (_focus_on_ring) { _hue += delta_hue; } else { mx -= 1.0; set_from_xy(mx, my); } consumed = true; break; case GDK_KEY_Right: case GDK_KEY_KP_Right: if (_focus_on_ring) { _hue -= delta_hue; } else { mx += 1.0; set_from_xy(mx, my); } consumed = true; break; } if (consumed) { if (_hue >= 1.0) _hue -= 1.0; if (_hue < 0.0) _hue += 1.0; _signal_color_changed.emit(); queue_draw(); } return consumed; } sigc::signal ColorWheel::signal_color_changed() { return _signal_color_changed; } } // Namespace Inkscape } } /* 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:fileencoding=utf-8:textwidth=99 :