From 8b4ca720369d790ea330bc2189efa05cc557c2f7 Mon Sep 17 00:00:00 2001
From: Joel Bodenmann <joel@unormal.org>
Date: Sat, 26 Apr 2014 03:27:19 +0200
Subject: [PATCH] Added gwinListEnableRender()

---
 demos/modules/gwin/list/main.c | 12 ++++--------
 docs/releases.txt              |  1 +
 src/gwin/list.c                | 20 ++++++++++++++++++++
 src/gwin/list.h                | 14 ++++++++++++++
 4 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/demos/modules/gwin/list/main.c b/demos/modules/gwin/list/main.c
index 36820c23..3811c36f 100644
--- a/demos/modules/gwin/list/main.c
+++ b/demos/modules/gwin/list/main.c
@@ -52,10 +52,6 @@ static void createWidgets(void) {
 	wi.text = "List 2: Smooth scrolling";
 	ghLabel1 = gwinLabelCreate(NULL, &wi);
 
-	// Make list widgets invisible by default as they would issue
-	// a re-render at every time an item is added
-	wi.g.show = FALSE;
-
 	// The first list widget
 	wi.g.width = 150;
 	wi.g.height = 100;
@@ -112,6 +108,9 @@ int main(void) {
 	gwinListAddItem(ghList1, "Item 13", FALSE);
 
 	// Add some items to the second list widget
+	// This time we will disable the render until
+	// all the items have been added
+	gwinListEnableRender(ghList2, FALSE);
 	gwinListAddItem(ghList2, "Item 0", FALSE);
 	gwinListAddItem(ghList2, "Item 1", FALSE);
 	gwinListAddItem(ghList2, "Item 2", FALSE);
@@ -126,10 +125,7 @@ int main(void) {
 	gwinListAddItem(ghList2, "Item 11", FALSE);
 	gwinListAddItem(ghList2, "Item 12", FALSE);
 	gwinListAddItem(ghList2, "Item 13", FALSE);
-	
-	// Make all the lists visible
-	gwinSetVisible(ghList1, TRUE);
-	gwinSetVisible(ghList2, TRUE);
+	gwinListEnableRender(ghList2, TRUE);
 
 	while(1) {
 		// Get an Event
diff --git a/docs/releases.txt b/docs/releases.txt
index 95bda6b1..3edfbf4c 100644
--- a/docs/releases.txt
+++ b/docs/releases.txt
@@ -23,6 +23,7 @@ FEATURE:	Added LGDP4532 driver by user shilow
 FEATURE:	Support for ChibiOS/RT 3.x
 FEATURE:	Added gwinProgressbarStop() and gwinProgressbarReset()
 FEATURE:	Added generic ILI93xx driver by xlh1460
+FEATURE:	Added gwinListEnableRender()
 
 
 *** changes after 1.9 ***
diff --git a/src/gwin/list.c b/src/gwin/list.c
index 8374ff39..50c669f0 100644
--- a/src/gwin/list.c
+++ b/src/gwin/list.c
@@ -41,6 +41,7 @@
 #define GLIST_FLG_HASIMAGES			(GWIN_FIRST_CONTROL_FLAG << 1)
 #define GLIST_FLG_SCROLLALWAYS		(GWIN_FIRST_CONTROL_FLAG << 2)
 #define GLIST_FLG_SCROLLSMOOTH      (GWIN_FIRST_CONTROL_FLAG << 3)
+#define GLIST_FLG_ENABLERENDER      (GWIN_FIRST_CONTROL_FLAG << 4)
 
 // Flags on a ListItem.
 #define GLIST_FLG_SELECTED			0x0001
@@ -92,6 +93,11 @@ static void gwinListDefaultDraw(GWidgetObject* gw, void* param) {
 		coord_t					sy;
 	#endif
 
+	// dont render if render has been disabled
+	if (!(gw->g.flags & GLIST_FLG_ENABLERENDER)) {
+		return;
+	}
+
 	ps = (gw->g.flags & GWIN_FLG_ENABLED) ? &gw->pstyle->enabled : &gw->pstyle->disabled;
 	iheight = gdispGetFontMetric(gw->g.font, fontHeight) + VERTICAL_PADDING;
 	x = 1;
@@ -401,12 +407,26 @@ GHandle gwinGListCreate(GDisplay *g, GListObject* gobj, GWidgetInit* pInit, bool
 	if (multiselect)
 		gobj->w.g.flags |= GLIST_FLG_MULTISELECT;
 	gobj->w.g.flags |= GLIST_FLG_SCROLLALWAYS;
+	gobj->w.g.flags |= GLIST_FLG_ENABLERENDER;
 
 	gwinSetVisible(&gobj->w.g, pInit->g.show);
 
 	return (GHandle)gobj;
 }
 
+void gwinListEnableRender(GHandle gh, bool_t ena) {
+	// is it a valid handle?
+	if (gh->vmt != (gwinVMT *)&listVMT)
+		return;
+
+	if (ena) {
+		gh->flags |= GLIST_FLG_ENABLERENDER;
+		gwinRedraw(gh);
+	} else {
+		gh->flags &=~ GLIST_FLG_ENABLERENDER;
+	}
+}
+
 void gwinListSetScroll(GHandle gh, scroll_t flag) {
 	// is it a valid handle?
 	if (gh->vmt != (gwinVMT *)&listVMT)
diff --git a/src/gwin/list.h b/src/gwin/list.h
index eb800439..2cc525a2 100644
--- a/src/gwin/list.h
+++ b/src/gwin/list.h
@@ -102,6 +102,20 @@ extern "C" {
 GHandle gwinGListCreate(GDisplay *g, GListObject *widget, GWidgetInit *pInit, bool_t multiselect);
 #define gwinListCreate(w, pInit, m)			gwinGListCreate(GDISP, w, pInit, m)
 
+/**
+ * @brief				Enable or disable the rendering of the list
+ *
+ * @details				Usually the list is being re-rendered when an item is added to the list. This can cause
+ * 						flickering and performance issues when many items are added at once. This can be prevented
+ *						by temporarely disabling the render using this function.
+ *
+ * @param[in] gh		The widget handle (must be a list handle)
+ * @param[in] ena		TRUE or FALSE
+ *
+ * @api
+ */
+void gwinListEnableRender(GHandle gh, bool_t ena);
+
 /**
  * @brief				Change the behaviour of the scroll bar
  *