feat(draw): draw shape from center if holding control

jtheoof · Feb 21, 2021 · d80c361 · d80c361
1 parent 616c6a6
commit d80c361
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Showing 8 changed files with 84 additions and 10 deletions.
diff --git a/README.md b/README.md
@@ -83,6 +83,10 @@ text_font=sans-serif
 
 <hr>
 
+- `Ctrl`: Center Shape (Rectangle & Ellipse) based on draw start
+
+<hr>
+
 - `Ctrl+z`: Undo
 - `Ctrl+Shift+z` or `Ctrl+y`: Redo
 - `Ctrl+s`: Save to file (see man page)

diff --git a/include/paint.h b/include/paint.h
@@ -7,7 +7,7 @@
 void paint_add_temporary(struct swappy_state *state, double x, double y,
                          enum swappy_paint_type type);
 void paint_update_temporary_shape(struct swappy_state *state, double x,
-                                  double y);
+                                  double y, gboolean is_control_pressed);
 void paint_update_temporary_text(struct swappy_state *state,
                                  GdkEventKey *event);
 void paint_update_temporary_text_clip(struct swappy_state *state, gdouble x,

diff --git a/include/swappy.h b/include/swappy.h
@@ -58,6 +58,7 @@ struct swappy_paint_shape {
   double b;
   double a;
   double w;
+  bool should_center_at_from;
   struct swappy_point from;
   struct swappy_point to;
   enum swappy_paint_type type;

diff --git a/res/swappy.glade b/res/swappy.glade
@@ -65,6 +65,7 @@
     <property name="show_menubar">False</property>
     <signal name="delete-event" handler="window_delete_handler" swapped="no"/>
     <signal name="key-press-event" handler="window_keypress_handler" swapped="no"/>
+    <signal name="key-release-event" handler="window_keyrelease_handler" swapped="no"/>
     <child>
       <object class="GtkOverlay">
         <property name="visible">True</property>

diff --git a/src/application.c b/src/application.c
@@ -291,6 +291,22 @@ void copy_clicked_handler(GtkWidget *widget, struct swappy_state *state) {
   clipboard_copy_drawing_area_to_selection(state);
 }
 
+void control_modifier_changed(bool pressed, struct swappy_state *state) {
+  if (state->temp_paint != NULL) {
+    switch (state->temp_paint->type) {
+      case SWAPPY_PAINT_MODE_ELLIPSE:
+      case SWAPPY_PAINT_MODE_RECTANGLE:
+        paint_update_temporary_shape(
+            state, state->temp_paint->content.shape.to.x,
+            state->temp_paint->content.shape.to.y, pressed);
+        render_state(state);
+        break;
+      default:
+        break;
+    }
+  }
+}
+
 void window_keypress_handler(GtkWidget *widget, GdkEventKey *event,
                              struct swappy_state *state) {
   if (state->temp_paint && state->mode == SWAPPY_PAINT_MODE_TEXT) {
@@ -384,6 +400,27 @@ void window_keypress_handler(GtkWidget *widget, GdkEventKey *event,
       case GDK_KEY_plus:
         action_stroke_size_increase(state);
         break;
+      case GDK_KEY_Control_L:
+        control_modifier_changed(true, state);
+        break;
+      default:
+        break;
+    }
+  }
+}
+
+void window_keyrelease_handler(GtkWidget *widget, GdkEventKey *event,
+                               struct swappy_state *state) {
+  if (event->state & GDK_CONTROL_MASK) {
+    switch (event->keyval) {
+      case GDK_KEY_Control_L:
+        control_modifier_changed(false, state);
+        break;
+      default:
+        break;
+    }
+  } else {
+    switch (event->keyval) {
       default:
         break;
     }
@@ -475,6 +512,7 @@ void draw_area_motion_notify_handler(GtkWidget *widget, GdkEventMotion *event,
   gdk_window_set_cursor(window, crosshair);
 
   gboolean is_button1_pressed = event->state & GDK_BUTTON1_MASK;
+  gboolean is_control_pressed = event->state & GDK_CONTROL_MASK;
 
   switch (state->mode) {
     case SWAPPY_PAINT_MODE_BLUR:
@@ -483,7 +521,7 @@ void draw_area_motion_notify_handler(GtkWidget *widget, GdkEventMotion *event,
     case SWAPPY_PAINT_MODE_ELLIPSE:
     case SWAPPY_PAINT_MODE_ARROW:
       if (is_button1_pressed) {
-        paint_update_temporary_shape(state, x, y);
+        paint_update_temporary_shape(state, x, y, is_control_pressed);
         render_state(state);
       }
       break;

diff --git a/src/paint.c b/src/paint.c
@@ -146,7 +146,7 @@ void paint_add_temporary(struct swappy_state *state, double x, double y,
 }
 
 void paint_update_temporary_shape(struct swappy_state *state, double x,
-                                  double y) {
+                                  double y, gboolean is_control_pressed) {
   struct swappy_paint *paint = state->temp_paint;
   struct swappy_point *point;
   GList *points;
@@ -171,6 +171,12 @@ void paint_update_temporary_shape(struct swappy_state *state, double x,
       break;
     case SWAPPY_PAINT_MODE_RECTANGLE:
     case SWAPPY_PAINT_MODE_ELLIPSE:
+      paint->can_draw = true;  // all set
+
+      paint->content.shape.should_center_at_from = is_control_pressed;
+      paint->content.shape.to.x = x;
+      paint->content.shape.to.y = y;
+      break;
     case SWAPPY_PAINT_MODE_ARROW:
       paint->can_draw = true;  // all set
 

diff --git a/src/render.c b/src/render.c
@@ -284,11 +284,22 @@ static void render_shape_arrow(cairo_t *cr, struct swappy_paint_shape shape) {
 static void render_shape_ellipse(cairo_t *cr, struct swappy_paint_shape shape) {
   double x = fabs(shape.from.x - shape.to.x);
   double y = fabs(shape.from.y - shape.to.y);
-  double xc = shape.from.x + ((shape.to.x - shape.from.x) / 2);
-  double yc = shape.from.y + ((shape.to.y - shape.from.y) / 2);
 
   double n = sqrt(x * x + y * y);
-  double r = n / 2;
+
+  double xc, yc, r;
+
+  if (shape.should_center_at_from) {
+    xc = shape.from.x;
+    yc = shape.from.y;
+
+    r = n;
+  } else {
+    xc = shape.from.x + ((shape.to.x - shape.from.x) / 2);
+    yc = shape.from.y + ((shape.to.y - shape.from.y) / 2);
+
+    r = n / 2;
+  }
 
   cairo_set_source_rgba(cr, shape.r, shape.g, shape.b, shape.a);
   cairo_set_line_width(cr, shape.w);
@@ -305,10 +316,19 @@ static void render_shape_ellipse(cairo_t *cr, struct swappy_paint_shape shape) {
 
 static void render_shape_rectangle(cairo_t *cr,
                                    struct swappy_paint_shape shape) {
-  double x = fmin(shape.from.x, shape.to.x);
-  double y = fmin(shape.from.y, shape.to.y);
-  double w = fabs(shape.from.x - shape.to.x);
-  double h = fabs(shape.from.y - shape.to.y);
+  double x, y, w, h;
+
+  if (shape.should_center_at_from) {
+    x = shape.from.x - fabs(shape.from.x - shape.to.x);
+    y = shape.from.y - fabs(shape.from.y - shape.to.y);
+    w = fabs(shape.from.x - shape.to.x) * 2;
+    h = fabs(shape.from.y - shape.to.y) * 2;
+  } else {
+    x = fmin(shape.from.x, shape.to.x);
+    y = fmin(shape.from.y, shape.to.y);
+    w = fabs(shape.from.x - shape.to.x);
+    h = fabs(shape.from.y - shape.to.y);
+  }
 
   cairo_set_source_rgba(cr, shape.r, shape.g, shape.b, shape.a);
   cairo_set_line_width(cr, shape.w);

diff --git a/swappy.1.scd b/swappy.1.scd
@@ -96,6 +96,10 @@ The following lines can be used as swappy's default:
 - *Equal*: Reset Stroke Size
 - *k*: Clear Paints (cannot be undone)
 
+## MODIFIERS
+
+- *Ctrl*: Center Shape (Rectangle & Ellipse) based on draw start
+
 ## HEADER BAR
 
 - *Ctrl+z*: Undo