Add a path editor demo

Add a simple demo for editing a poly-Bezier curve.

tests/curve-editor.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+#define CURVE_TYPE_EDITOR (curve_editor_get_type ())
+G_DECLARE_FINAL_TYPE (CurveEditor, curve_editor, CURVE, EDITOR, GtkWidget)
+
+GtkWidget * curve_editor_new      (void);
+
+void        curve_editor_set_edit (CurveEditor *self,
+                                   gboolean     edit);
+
+void        curve_editor_set_path (CurveEditor *self,
+                                   GskPath     *path);
+
+GskPath *   curve_editor_get_path (CurveEditor *self);
+
+void        curve_editor_set_stroke (CurveEditor *self,
+                                     GskStroke   *stroke);
+
+const GskStroke *
+            curve_editor_get_stroke (CurveEditor *self);
+
+
+void        curve_editor_set_color  (CurveEditor *self,
+                                     GdkRGBA     *color);
+
+const GdkRGBA *
+            curve_editor_get_color  (CurveEditor *self);
+
+G_END_DECLS

tests/curve.c

@@ -0,0 +1,184 @@
+#include <gtk/gtk.h>
+#include "curve-editor.h"
+
+
+static GskPath *
+make_circle_path (void)
+{
+  float w = 200;
+  float h = 200;
+  float cx = w / 2;
+  float cy = h / 2;
+  float pad = 20;
+  float r = (w - 2 * pad) / 2;
+  float k = 0.55228;
+  float kr = k  * r;
+  GskPathBuilder *builder;
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_builder_move_to (builder,  cx, pad);
+  gsk_path_builder_curve_to (builder, cx + kr, pad,
+                                      w - pad, cy - kr,
+                                      w - pad, cy);
+  gsk_path_builder_curve_to (builder, w - pad, cy + kr,
+                                      cx + kr, h - pad,
+                                      cx, h - pad);
+  gsk_path_builder_curve_to (builder, cx - kr, h - pad,
+                                      pad, cy + kr,
+                                      pad, cy);
+  gsk_path_builder_curve_to (builder, pad, cy - kr,
+                                      cx - kr, pad,
+                                      cx, pad);
+  gsk_path_builder_close (builder);
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+static void
+edit_changed (GtkToggleButton *button,
+              GParamSpec      *pspec,
+              CurveEditor     *editor)
+{
+  curve_editor_set_edit (editor, gtk_toggle_button_get_active (button));
+}
+
+static void
+reset (GtkButton   *button,
+       CurveEditor *editor)
+{
+  GskPath *path;
+
+  path = make_circle_path ();
+  curve_editor_set_path (editor, path);
+  gsk_path_unref (path);
+}
+
+static void
+width_changed (GtkRange    *range,
+               CurveEditor *editor)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_line_width (stroke, gtk_range_get_value (range));
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+cap_changed (GtkDropDown *combo,
+             GParamSpec  *pspec,
+             CurveEditor *editor)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_line_cap (stroke, (GskLineCap)gtk_drop_down_get_selected (combo));
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+join_changed (GtkDropDown *combo,
+              GParamSpec  *pspec,
+              CurveEditor *editor)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_line_join (stroke, (GskLineJoin)gtk_drop_down_get_selected (combo));
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+color_changed (GtkColorChooser *chooser,
+               CurveEditor     *editor)
+{
+  GdkRGBA color;
+
+  gtk_color_chooser_get_rgba (chooser, &color);
+  curve_editor_set_color (editor, &color);
+}
+
+int
+main (int argc, char *argv[])
+{
+  GtkWindow *window;
+  GtkWidget *demo;
+  GtkWidget *edit_toggle;
+  GtkWidget *reset_button;
+  GtkWidget *titlebar;
+  GtkWidget *scale;
+  GtkWidget *stroke_button;
+  GtkWidget *popover;
+  GtkWidget *grid;
+  GtkWidget *cap_combo;
+  GtkWidget *join_combo;
+  GtkWidget *color_button;
+
+  gtk_init ();
+
+  window = GTK_WINDOW (gtk_window_new ());
+  gtk_window_set_default_size (GTK_WINDOW (window), 250, 250);
+
+  edit_toggle = gtk_toggle_button_new ();
+  gtk_button_set_icon_name (GTK_BUTTON (edit_toggle), "document-edit-symbolic");
+
+  reset_button = gtk_button_new_from_icon_name ("edit-undo-symbolic");
+
+  stroke_button = gtk_menu_button_new ();
+  gtk_menu_button_set_icon_name (GTK_MENU_BUTTON (stroke_button), "open-menu-symbolic");
+  popover = gtk_popover_new ();
+  gtk_menu_button_set_popover (GTK_MENU_BUTTON (stroke_button), popover);
+
+  grid = gtk_grid_new ();
+  gtk_grid_set_row_spacing (GTK_GRID (grid), 6);
+  gtk_grid_set_column_spacing (GTK_GRID (grid), 6);
+  gtk_popover_set_child (GTK_POPOVER (popover), grid);
+
+  gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line Width:"), 0, 0, 1, 1);
+  scale = gtk_scale_new_with_range (GTK_ORIENTATION_HORIZONTAL, 1, 10, 1);
+  gtk_widget_set_size_request (scale, 60, -1);
+  gtk_grid_attach (GTK_GRID (grid), scale, 1, 0, 1, 1);
+
+  gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line cap:"), 0, 1, 1, 1);
+  cap_combo = gtk_drop_down_new_from_strings ((const char *[]){"Butt", "Round", "Square", NULL});
+  gtk_grid_attach (GTK_GRID (grid), cap_combo, 1, 1, 1, 1);
+
+  gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line join:"), 0, 2, 1, 1);
+  join_combo = gtk_drop_down_new_from_strings ((const char *[]){"Miter", "Round", "Bevel", NULL});
+  gtk_grid_attach (GTK_GRID (grid), join_combo, 1, 2, 1, 1);
+
+  gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Stroke color:"), 0, 3, 1, 1);
+  color_button = gtk_color_button_new_with_rgba (&(GdkRGBA){ 0., 0., 0., 1.});
+  gtk_grid_attach (GTK_GRID (grid), color_button, 1, 3, 1, 1);
+
+  titlebar = gtk_header_bar_new ();
+  gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), edit_toggle);
+  gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), reset_button);
+  gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), stroke_button);
+
+  gtk_window_set_titlebar (GTK_WINDOW (window), titlebar);
+
+  demo = curve_editor_new ();
+
+  g_signal_connect (edit_toggle, "notify::active", G_CALLBACK (edit_changed), demo);
+  g_signal_connect (reset_button, "clicked", G_CALLBACK (reset), demo);
+  g_signal_connect (scale, "value-changed", G_CALLBACK (width_changed), demo);
+  g_signal_connect (cap_combo, "notify::selected", G_CALLBACK (cap_changed), demo);
+  g_signal_connect (join_combo, "notify::selected", G_CALLBACK (join_changed), demo);
+  g_signal_connect (color_button, "color-set", G_CALLBACK (color_changed), demo);
+
+  reset (NULL, CURVE_EDITOR (demo));
+
+  gtk_window_set_child (window, demo);
+
+  gtk_window_present (window);
+
+  while (g_list_model_get_n_items (gtk_window_get_toplevels ()) > 0)
+    g_main_context_iteration (NULL, TRUE);
+
+  return 0;
+}

tests/meson.build

@@ -1,5 +1,6 @@
 gtk_tests = [
   # testname, optional extra sources
+  ['curve', ['curve.c', 'curve-editor.c']],
   ['curve2'],
   ['testupload'],
   ['testtransform'],