Refactor the panning code into separate functions, and correct a comment

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18865 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/jpeg/jpeg.c

@@ -463,54 +463,13 @@ int show_menu(void) /* return 1 to quit */
     menu_exit(m);
     return 0;
 }
-/* interactively scroll around the image */
-int scroll_bmp(struct t_disp* pdisp)
-{
-    int lastbutton = 0;
 
-    while (true)
+/* Pan the viewing window right - move image to the left and fill in
-    {
+   the right-hand side */
-        int button;
+static void pan_view_right(struct t_disp* pdisp)
+{
     int move;
 
-        if (slideshow_enabled)
-            button = rb->button_get_w_tmo(jpeg_settings.ss_timeout * HZ);
-        else button = rb->button_get(true);
-
-        running_slideshow = false;
-
-        switch(button)
-        {
-        case JPEG_LEFT:
-            if (!(ds < ds_max) && entries > 0 && jpg.x_size <= MAX_X_SIZE)
-                return change_filename(DIR_PREV);
-        case JPEG_LEFT | BUTTON_REPEAT:
-            move = MIN(HSCROLL, pdisp->x);
-            if (move > 0)
-            {
-                MYXLCD(scroll_right)(move); /* scroll right */
-                pdisp->x -= move;
-#ifdef HAVE_LCD_COLOR
-                yuv_bitmap_part(
-                    pdisp->bitmap, pdisp->csub_x, pdisp->csub_y,
-                    pdisp->x, pdisp->y, pdisp->stride,
-                    0, MAX(0, (LCD_HEIGHT-pdisp->height)/2), /* x, y */
-                    move, MIN(LCD_HEIGHT, pdisp->height),    /* w, h */
-                    jpeg_settings.colour_mode, jpeg_settings.dither_mode);
-#else
-                MYXLCD(gray_bitmap_part)(
-                    pdisp->bitmap[0], pdisp->x, pdisp->y, pdisp->stride,
-                    0, MAX(0, (LCD_HEIGHT-pdisp->height)/2), /* x, y */
-                    move, MIN(LCD_HEIGHT, pdisp->height));   /* w, h */
-#endif
-                MYLCD_UPDATE();
-            }
-            break;
-
-        case JPEG_RIGHT:
-            if (!(ds < ds_max) && entries > 0 && jpg.x_size <= MAX_X_SIZE)
-                return change_filename(DIR_NEXT);
-        case JPEG_RIGHT | BUTTON_REPEAT:
     move = MIN(HSCROLL, pdisp->width - pdisp->x - LCD_WIDTH);
     if (move > 0)
     {
@@ -532,10 +491,43 @@ int scroll_bmp(struct t_disp* pdisp)
 #endif
         MYLCD_UPDATE();
     }
-            break;
+}
+
+/* Pan the viewing window left - move image to the right and fill in
+   the left-hand side */
+static void pan_view_left(struct t_disp* pdisp)
+{
+    int move;
+
+    move = MIN(HSCROLL, pdisp->x);
+    if (move > 0)
+    {
+        MYXLCD(scroll_right)(move); /* scroll right */
+        pdisp->x -= move;
+#ifdef HAVE_LCD_COLOR
+        yuv_bitmap_part(
+            pdisp->bitmap, pdisp->csub_x, pdisp->csub_y,
+            pdisp->x, pdisp->y, pdisp->stride,
+            0, MAX(0, (LCD_HEIGHT-pdisp->height)/2), /* x, y */
+            move, MIN(LCD_HEIGHT, pdisp->height),    /* w, h */
+            jpeg_settings.colour_mode, jpeg_settings.dither_mode);
+#else
+        MYXLCD(gray_bitmap_part)(
+            pdisp->bitmap[0], pdisp->x, pdisp->y, pdisp->stride,
+            0, MAX(0, (LCD_HEIGHT-pdisp->height)/2), /* x, y */
+            move, MIN(LCD_HEIGHT, pdisp->height));   /* w, h */
+#endif
+        MYLCD_UPDATE();
+    }
+}
+
+
+/* Pan the viewing window up - move image down and fill in
+   the top */
+static void pan_view_up(struct t_disp* pdisp)
+{
+    int move;
 
-        case JPEG_UP:
-        case JPEG_UP | BUTTON_REPEAT:
     move = MIN(VSCROLL, pdisp->y);
     if (move > 0)
     {
@@ -563,10 +555,14 @@ int scroll_bmp(struct t_disp* pdisp)
 #endif
         MYLCD_UPDATE();
     }
-            break;
+}
+
+/* Pan the viewing window down - move image up and fill in
+   the bottom */
+static void pan_view_down(struct t_disp* pdisp)
+{
+    int move;
 
-        case JPEG_DOWN:
-        case JPEG_DOWN | BUTTON_REPEAT:
     move = MIN(VSCROLL, pdisp->height - pdisp->y - LCD_HEIGHT);
     if (move > 0)
     {
@@ -609,7 +605,48 @@ int scroll_bmp(struct t_disp* pdisp)
 #endif
         MYLCD_UPDATE();
     }
+}
+
+/* interactively scroll around the image */
+int scroll_bmp(struct t_disp* pdisp)
+{
+    int button;
+    int lastbutton = 0;
+
+    while (true)
+    {
+        if (slideshow_enabled)
+            button = rb->button_get_w_tmo(jpeg_settings.ss_timeout * HZ);
+        else button = rb->button_get(true);
+
+        running_slideshow = false;
+
+        switch(button)
+        {
+        case JPEG_LEFT:
+            if (!(ds < ds_max) && entries > 0 && jpg.x_size <= MAX_X_SIZE)
+                return change_filename(DIR_PREV);
+        case JPEG_LEFT | BUTTON_REPEAT:
+            pan_view_left(pdisp);
             break;
+
+        case JPEG_RIGHT:
+            if (!(ds < ds_max) && entries > 0 && jpg.x_size <= MAX_X_SIZE)
+                return change_filename(DIR_NEXT);
+        case JPEG_RIGHT | BUTTON_REPEAT:
+            pan_view_right(pdisp);
+            break;
+
+        case JPEG_UP:
+        case JPEG_UP | BUTTON_REPEAT:
+            pan_view_up(pdisp);
+            break;
+
+        case JPEG_DOWN:
+        case JPEG_DOWN | BUTTON_REPEAT:
+            pan_view_down(pdisp);
+            break;
+
         case BUTTON_NONE:
             if (!slideshow_enabled)
                 break;
@@ -1194,8 +1231,8 @@ enum plugin_status plugin_start(const struct plugin_api* api, const void* parame
     xlcd_init(rb);
 #endif
 
-    /* should be ok to just load settings since a parameter is present
+    /* should be ok to just load settings since the plugin itself has
-       here and the drive should be spinning */
+       just been loaded from disk and the drive should be spinning */
     configfile_init(rb);
     configfile_load(JPEG_CONFIGFILE, jpeg_config,
                     ARRAYLEN(jpeg_config), JPEG_SETTINGS_MINVERSION);