Add trim mode

src/canvas.c

@@ -237,6 +237,8 @@ int canvas_resize(Canvas **canvas_pointer, int newrows, int newcols) {
  * Requires a pointer to a canvas pointer.
  *
  * Returns 1 if the canvas was truncated, 0 otherwise.
+ *
+ * TODO: update docstring
  */
 Canvas *canvas_trimc(Canvas *orig, char ignore, bool right, bool bottom,
                      bool left, bool top) {
@@ -353,6 +355,7 @@ Canvas *canvas_trimc(Canvas *orig, char ignore, bool right, bool bottom,
                          (right ? mr : orig->num_cols - 1));
 }
 
+// TODO: drop this or fill it out
 inline Canvas *canvas_trim(Canvas *orig, int right, int bottom, int left,
                            int top) {}
 

src/fe_modes.c

@@ -39,6 +39,7 @@ editor_mode_t modes[] = {
     {"Pan", "Pan around the canvas", mode_pan},
     {"Free-Line", "Draw a line with your arrow keys", mode_free_line},
     {"Brush", "Paint with arrow keys and mouse", mode_brush},
+    {"Trim", "Remove empty space", mode_trim},
 };
 
 typedef struct {
@@ -475,3 +476,39 @@ int mode_brush(reason_t reason, State *state) {
 
   return 0;
 }
+
+/* mode_trim
+ *
+ * Trim edges of the canvas.
+ *
+ * Select a direction to trim and
+ */
+int mode_trim(reason_t reason, State *state) {
+  if (reason == NEW_KEY) {
+    int dir = 0;  // 0: top, 1: right, 2: down, 3: left
+    switch (state->ch_in) {
+      case KEY_UP:
+        dir = 0;
+        break;
+      case KEY_RIGHT:
+        dir = 1;
+        break;
+      case KEY_DOWN:
+        dir = 2;
+        break;
+      case KEY_LEFT:
+        dir = 3;
+        break;
+      default:
+        return 0;
+    }
+    Canvas *old_canvas = state->view->canvas;
+    // trimc order   :        right     bottom    left      top
+    Canvas *new_canvas =
+        canvas_trimc(old_canvas, ' ', dir == 1, dir == 2, dir == 3, dir == 0);
+    state->view->canvas = new_canvas;
+    canvas_free(old_canvas);
+    redraw_canvas_win();
+  }
+  return 0;
+}

src/fe_modes.h

@@ -17,6 +17,7 @@ mode_function_t mode_insert;
 mode_function_t mode_pan;
 mode_function_t mode_free_line;
 mode_function_t mode_brush;
+mode_function_t mode_trim;
 
 typedef struct {
   char *name;

src/mode_id.h

@@ -12,6 +12,7 @@ typedef enum {
   MODE_PAN,
   MODE_FREE_LINE,
   MODE_BRUSH,
+  MODE_TRIM,
 
   // ^ add your mode above
   LAST,  // used to get number of elements