Add support for ui:touch extension (not tested in a host)

pui/lv2pui.cpp

@@ -27,12 +27,17 @@ void LV2PUi::Instantiate(
 	LV2UI_Widget *widget,
 	const LV2_Feature *const *features)
 {
+	this->resize = NULL;
+	this->touch = NULL;
+
 	PuglNativeWindow parent = 0;
 	for (; features && *features; ++features) {
 		if (!strcmp((*features)->URI, LV2_UI__parent)) {
 			parent = (PuglNativeWindow)(*features)->data;
 		} else if (!strcmp((*features)->URI, LV2_UI__resize)) {
 			this->resize = (LV2UI_Resize *)(*features)->data;
+		} else if (!strcmp((*features)->URI, LV2_UI__touch)) {
+			this->touch = (LV2UI_Touch *)(*features)->data;
 		}
 	}
 
@@ -78,6 +83,13 @@ LV2PUi::~LV2PUi()
 {
 }
 
+void LV2PUi::WidgetGrabbed(const Widget *widget, bool grabbed)
+{
+	if (this->touch) {
+		this->touch->touch(this, widget->port, grabbed);
+	}
+}
+
 static void lv2pui_cleanup(LV2UI_Handle handle)
 {
 	LV2PUi *lv2pui = (LV2PUi *)handle;

pui/lv2pui.h

@@ -12,6 +12,7 @@ struct LV2PUi : PUi {
 	LV2UI_Write_Function write;
 	LV2UI_Controller controller;
 	LV2UI_Resize *resize;
+	LV2UI_Touch *touch;
 
 	virtual ~LV2PUi();
 
@@ -27,6 +28,8 @@ struct LV2PUi : PUi {
 	virtual void PortEvent(uint32_t port_index, uint32_t buffer_size, uint32_t format, const void *buffer);
 
 	/* virtual */ void ParameterChanged(const Widget *w);
+
+	/* virtual */ void WidgetGrabbed(const Widget *widget, bool grabbed);
 };
 
 struct StringCompare {

pui/pui.cpp

@@ -125,6 +125,10 @@ void PUi::OnMouse(int button, bool press, int x, int y)
 		this->mb &= ~(1 << button);
 	}
 
+	if (this->active) {
+		this->WidgetGrabbed(this->active, this->mb);
+	}
+
 	if (!this->mb) {
 		/* No button press, check for widget focus change */
 		Widget *w = this->widget->GetWidget(x, y);

pui/pui.h

@@ -63,6 +63,8 @@ struct PUi : PTextures {
 	virtual void ParameterChanged(const Widget *widget) = 0;
 
 	void SetFunc();
+
+	virtual void WidgetGrabbed(const Widget *widget, bool grabbed) {}
 };
 
 #endif /* PUI_H */