[GitHub] [incubator-nuttx] v01d commented on a change in pull request #2208: lcd: add optional putarea()/getarea() operations

[GitBox <gi...@apache.org>]

v01d commented on a change in pull request #2208:
URL: https://github.com/apache/incubator-nuttx/pull/2208#discussion_r516819366



##########
File path: drivers/lcd/lcd_dev.c
##########
@@ -123,20 +123,56 @@ static int lcddev_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
     {
     case LCDDEVIO_GETRUN:
       {
-        FAR struct lcddev_run_s *lcd_putrun =
+        FAR struct lcddev_run_s *lcd_run =
             (FAR struct lcddev_run_s *)arg;
 
-        ret = priv->planeinfo.getrun(lcd_putrun->row, lcd_putrun->col,
-                                     lcd_putrun->data, lcd_putrun->npixels);
+        ret = priv->planeinfo.getrun(lcd_run->row, lcd_run->col,
+                                     lcd_run->data, lcd_run->npixels);
       }
       break;
     case LCDDEVIO_PUTRUN:
       {
-        const FAR struct lcddev_run_s *lcd_putrun =
+        const FAR struct lcddev_run_s *lcd_run =
             (const FAR struct lcddev_run_s *)arg;
 
-        ret = priv->planeinfo.putrun(lcd_putrun->row, lcd_putrun->col,
-                                     lcd_putrun->data, lcd_putrun->npixels);
+        ret = priv->planeinfo.putrun(lcd_run->row, lcd_run->col,
+                                     lcd_run->data, lcd_run->npixels);
+      }
+      break;
+    case LCDDEVIO_PUTAREA:
+      {
+        const FAR struct lcddev_area_s *lcd_area =
+            (const FAR struct lcddev_area_s *)arg;
+
+        if (priv->planeinfo.putarea)
+          {
+            ret = priv->planeinfo.putarea(lcd_area->row_start,

Review comment:
       But the LCD framebuffer driver simply emulates a framebuffer over LCD operations. In fact, with the putarea() interface, you can achieve the same behavior as the LCD framebuffer has now, which blits the entire buffer using putrun() for each call. So, you can get the same results by just doing putarea() over the whole display whenever you want.




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