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authorLeo Tenenbaum <pommicket@gmail.com>2020-12-14 17:59:46 -0500
committerLeo Tenenbaum <pommicket@gmail.com>2020-12-14 17:59:46 -0500
commit4ddf0821a9a24f6e6a6ca60ab6d38e095a88591b (patch)
treea40b6a51ae892637fcb2823e3f2fa3cf4e8f021d /buffer.c
parentb006db3fe4da1beb38909232ceaf1c370415c61a (diff)
scroll to cursor
Diffstat (limited to 'buffer.c')
-rw-r--r--buffer.c52
1 files changed, 48 insertions, 4 deletions
diff --git a/buffer.c b/buffer.c
index c0213ea..42c5ee3 100644
--- a/buffer.c
+++ b/buffer.c
@@ -442,18 +442,62 @@ bool buffer_pos_move_down(TextBuffer *buffer, BufferPos *pos) {
return true;
}
+// if the cursor is offscreen, this will scroll to make it onscreen.
+static void buffer_scroll_to_cursor(TextBuffer *buffer) {
+ i64 cursor_line = buffer->cursor_pos.line;
+ i64 cursor_col = buffer_index_to_column(buffer, (u32)cursor_line, buffer->cursor_pos.index);
+ i64 display_lines = buffer_display_rows(buffer);
+ i64 display_cols = buffer_display_cols(buffer);
+ double scroll_x = buffer->scroll_x, scroll_y = buffer->scroll_y;
+ i64 scroll_padding = 5;
+
+ // scroll left if cursor is off screen in that direction
+ double max_scroll_x = (double)(cursor_col - scroll_padding);
+ scroll_x = util_mind(scroll_x, max_scroll_x);
+ // scroll right
+ double min_scroll_x = (double)(cursor_col - display_cols + scroll_padding);
+ scroll_x = util_maxd(scroll_x, min_scroll_x);
+ // scroll up
+ double max_scroll_y = (double)(cursor_line - scroll_padding);
+ scroll_y = util_mind(scroll_y, max_scroll_y);
+ // scroll down
+ double min_scroll_y = (double)(cursor_line - display_lines + scroll_padding);
+ scroll_y = util_maxd(scroll_y, min_scroll_y);
+
+ buffer->scroll_x = scroll_x;
+ buffer->scroll_y = scroll_y;
+ buffer_correct_scroll(buffer); // it's possible that min/max_scroll_x/y go too far
+}
+
bool buffer_cursor_move_left(TextBuffer *buffer) {
- return buffer_pos_move_left(buffer, &buffer->cursor_pos);
+ if (buffer_pos_move_left(buffer, &buffer->cursor_pos)) {
+ buffer_scroll_to_cursor(buffer);
+ return true;
+ }
+ return false;
}
bool buffer_cursor_move_right(TextBuffer *buffer) {
- return buffer_pos_move_right(buffer, &buffer->cursor_pos);
+ if (buffer_pos_move_right(buffer, &buffer->cursor_pos)) {
+ buffer_scroll_to_cursor(buffer);
+ return true;
+ }
+ return false;
}
bool buffer_cursor_move_up(TextBuffer *buffer) {
- return buffer_pos_move_up(buffer, &buffer->cursor_pos);
+ if (buffer_pos_move_up(buffer, &buffer->cursor_pos)) {
+ buffer_scroll_to_cursor(buffer);
+ return true;
+ }
+ return false;
}
bool buffer_cursor_move_down(TextBuffer *buffer) {
- return buffer_pos_move_down(buffer, &buffer->cursor_pos);
+ if (buffer_pos_move_down(buffer, &buffer->cursor_pos)) {
+ buffer_scroll_to_cursor(buffer);
+ return true;
+ }
+ return false;
}
+