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 {
@@ -159,26 +160,35 @@ int master_handler(State *state, WINDOW *canvas_win, WINDOW *status_win) {
     // shift view down/up/left/right
     // renaming for ease of use
     const int h = getmaxy(canvas_win) - 2;  // height of visible canvas
-    const int w = getmaxx(canvas_win) - 2;  // width
+    const int w = getmaxx(canvas_win) - 2;  // width of visible canvas
     const int vy = state->view->y;
     const int vx = state->view->x;
-    const int ch = state->view->canvas->num_rows;
-    const int cw = state->view->canvas->num_cols;
+    const int ch = state->view->canvas->num_rows;  // height of total canvas
+    const int cw = state->view->canvas->num_cols;  // width of total canvas
     int new_vy = vy;
     int new_vx = vx;
     // calc shift based on key
     switch (c) {
       case KEY_NPAGE:  // down
-        new_vy = min(vy + h, ch - h);
+        // b/c canvas snaps to the top left corner, we need to be more careful
+        // when moving down or right. Move to either:
+        //           another window height
+        //           |       or the end of the visible canvas
+        //           |       | (when the canvas is smaller than the window, this
+        //           v       v is less than zero, so get the max of the two)
+        new_vy = min(vy + h, max(ch - h, 0));
         break;
       case KEY_PPAGE:  // up
         new_vy = max(0, vy - h);
         break;
-      case KEY_SRIGHT:
-        new_vx = min(vx + w, cw - w);
+      case KEY_SRIGHT:  // right
+        // similar situation to moving down - jump to another window width or
+        // the end of the canvas, and check for negative values
+        new_vx = min(vx + w, max(cw - w, 0));
         break;
-      case KEY_SLEFT:
+      case KEY_SLEFT:  // left
         new_vx = max(0, vx - w);
+        break;
     }
     // shift view
     state->view->y = new_vy;
@@ -199,6 +209,36 @@ int master_handler(State *state, WINDOW *canvas_win, WINDOW *status_win) {
     call_mode(state->current_mode, NEW_KEY, state);
   }
 
+  // Check if view and/or cursor is out of bounds and snap back
+  {
+    View *v = state->view;
+    const int max_x = v->canvas->num_cols - 1;
+    const int max_y = v->canvas->num_rows - 1;
+    if (v->x > max_x) {
+      v->x = max_x;
+      logd("Snapped view to max width\n");
+    }
+    if (v->y > max_y) {
+      v->y = max_y;
+      logd("Snapped view to max height\n");
+    }
+    Cursor *c = state->cursor;
+    bool redraw_flag = false;
+    if (c->x + v->x > max_x) {
+      c->x = max_x - v->x;
+      logd("Snapped cursor to max x\n");
+      redraw_flag = true;
+    }
+    if (c->y + v->y > max_y) {
+      c->y = max_y - v->y;
+      logd("Snapped cursor to max y\n");
+      redraw_flag = true;
+    }
+    if (redraw_flag) {
+      redraw_canvas_win();
+    }
+  }
+
   // Move UI cursor to the right place
   wmove(canvas_win, cursor_y_to_canvas(state->cursor),
         cursor_x_to_canvas(state->cursor));
@@ -475,3 +515,39 @@ 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/frontend.c

@@ -321,13 +321,8 @@ void front_setcharcursor(char ch) {
 
 void redraw_canvas_win() {
   // find max ranges to draw canvas
-  int max_x = view_max_x;
-  int max_y = view_max_y;
-
-  if (max_x >= view->canvas->num_cols - view->x)
-    (max_x = view->canvas->num_cols - view->x);
-  if (max_y >= view->canvas->num_rows - view->y)
-    (max_y = view->canvas->num_rows - view->y);
+  int max_x = min(view_max_x, view->canvas->num_cols - view->x);
+  int max_y = min(view_max_y, view->canvas->num_rows - view->y);
 
   // draw canvas onto window
   for (int x = 0; x < max_x; x++) {
@@ -338,12 +333,12 @@ void redraw_canvas_win() {
   }
 
   // draw fill in rest of window
-  for (int x = max_x; x < view_max_x; x++) {
+  for (int x = max(0, max_x); x < view_max_x; x++) {
     for (int y = 0; y < view_max_y; y++) {
       mvwaddch(canvas_win, y + 1, x + 1, ACS_CKBOARD);
     }
   }
-  for (int y = max_y; y < view_max_y; y++) {
+  for (int y = max(0, max_y); y < view_max_y; y++) {
     for (int x = 0; x < max_x; x++) {
       mvwaddch(canvas_win, y + 1, x + 1, ACS_CKBOARD);
     }

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