console: add function to erase buffer

New function which helps erasing a whole region of the buffer.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

diff --git a/src/console.h b/src/console.h
index 7df814d..7665d58 100644 (file)
--- a/src/console.h
+++ b/src/console.h
@@ -72,6 +72,8 @@ kmscon_symbol_t kmscon_buffer_read(struct kmscon_buffer *buf, unsigned int x,
                                                        unsigned int y);
 void kmscon_buffer_scroll_down(struct kmscon_buffer *buf, unsigned int num);
 void kmscon_buffer_scroll_up(struct kmscon_buffer *buf, unsigned int num);
+void kmscon_buffer_erase_region(struct kmscon_buffer *buf, unsigned int x_from,
+               unsigned int y_from, unsigned int x_to, unsigned int y_to);
 
 /* console objects */
 

diff --git a/src/console_cell.c b/src/console_cell.c
index 8ef2898..37758ec 100644 (file)
--- a/src/console_cell.c
+++ b/src/console_cell.c
@@ -137,6 +137,14 @@ static int init_cell(struct cell *cell)
        return 0;
 }
 
+static void reset_cell(struct cell *cell)
+{
+       if (!cell)
+               return;
+
+       memset(cell, 0, sizeof(*cell));
+}
+
 static void free_line(struct line *line)
 {
        unsigned int i;
@@ -201,6 +209,21 @@ static int resize_line(struct line *line, unsigned int width)
        return 0;
 }
 
+static struct line *get_line(struct kmscon_buffer *buf, unsigned int y)
+{
+       if (y < buf->mtop_y) {
+               return buf->mtop_buf[y];
+       } else if (y < buf->mtop_y + buf->scroll_y) {
+               y -= buf->mtop_y;
+               return buf->scroll_buf[y];
+       } else if (y < buf->mtop_y + buf->scroll_y + buf->mbottom_y) {
+               y = y - buf->mtop_y - buf->scroll_y;
+               return buf->mbottom_buf[y];
+       }
+
+       return NULL;
+}
+
 int kmscon_buffer_new(struct kmscon_buffer **out, unsigned int x,
                                                                unsigned int y)
 {
@@ -878,3 +901,32 @@ void kmscon_buffer_scroll_up(struct kmscon_buffer *buf, unsigned int num)
                                                num * sizeof(struct line*));
        buf->scroll_fill = buf->scroll_y;
 }
+
+void kmscon_buffer_erase_region(struct kmscon_buffer *buf, unsigned int x_from,
+               unsigned int y_from, unsigned int x_to, unsigned int y_to)
+{
+       unsigned int to;
+       struct line *line;
+
+       if (!buf)
+               return;
+
+       if (y_to >= buf->size_y)
+               y_to = buf->size_y - 1;
+       if (x_to >= buf->size_x)
+               x_to = buf->size_x - 1;
+
+       for ( ; y_from <= y_to; ++y_from) {
+               line = get_line(buf, y_from);
+               if (y_from == y_to)
+                       to = x_to;
+               else
+                       to = buf->size_x - 1;
+               for ( ; x_from <= to; ++x_from) {
+                       if (x_from >= line->size)
+                               break;
+                       reset_cell(&line->cells[x_from]);
+               }
+               x_from = 0;
+       }
+}