From 6ef5e10e660a4fb0021090e78ba756332950af5d Mon Sep 17 00:00:00 2001
From: Juergen Spitzmueller <spitz@lyx.org>
Date: Sun, 12 Nov 2017 14:44:18 +0100
Subject: [PATCH] InsetExternal: update renderer after preview status change

This fixes a crash when changing instant preview prefs while
document with previewed external inset is opened.

Fixes: #10785
(cherry picked from commit 0842e22f4551e84dbf24259c65994c760fc22925)
---
 src/insets/InsetExternal.cpp | 36 ++++++++++++++++++++++++++++--------
 src/insets/InsetExternal.h   |  8 ++++++--
 status.22x                   |  3 +++
 3 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/src/insets/InsetExternal.cpp b/src/insets/InsetExternal.cpp
index 4122cfdb05..cb1bc7bda1 100644
--- a/src/insets/InsetExternal.cpp
+++ b/src/insets/InsetExternal.cpp
@@ -520,12 +520,18 @@ bool InsetExternal::showInsetDialog(BufferView * bv) const
 
 void InsetExternal::metrics(MetricsInfo & mi, Dimension & dim) const
 {
+	if (!isRendererValid())
+		updatePreview();
+
 	renderer_->metrics(mi, dim);
 }
 
 
 void InsetExternal::draw(PainterInfo & pi, int x, int y) const
 {
+	if (!isRendererValid())
+		updatePreview();
+
 	if (renderer_->asButton())
 		renderer_->setRenderState(mouse_hover_[pi.base.bv]);
 	renderer_->draw(pi, x, y);
@@ -592,9 +598,22 @@ InsetExternalParams const & InsetExternal::params() const
 }
 
 
-void InsetExternal::updatePreview()
+bool InsetExternal::isPreviewed() const
 {
-	setParams(params_);
+	return (external::getTemplatePtr(params_) && !params_.filename.empty()
+		&& params_.display
+		&& lyxrc.display_graphics
+		&& params_.preview_mode != PREVIEW_OFF
+		&& (params_.preview_mode != PREVIEW_INSTANT
+		    || RenderPreview::previewText()));
+}
+
+
+bool InsetExternal::isRendererValid() const
+{
+	if (!renderer_->asButton())
+		return isPreviewed();
+	return !isPreviewed();
 }
 
 
@@ -606,12 +625,13 @@ void InsetExternal::setParams(InsetExternalParams const & p)
 	// will use this.
 	defaultTemplateName = params_.templatename();
 
-	if (!external::getTemplatePtr(params_) || params_.filename.empty()
-		|| !params_.display
-		|| !lyxrc.display_graphics
-		|| params_.preview_mode == PREVIEW_OFF
-		|| (params_.preview_mode == PREVIEW_INSTANT
-		    && !RenderPreview::previewText())) {
+	updatePreview();
+}
+
+
+void InsetExternal::updatePreview() const
+{
+	if (!isPreviewed()) {
 		RenderButton * button_ptr = renderer_->asButton();
 		if (!button_ptr) {
 			renderer_.reset(new RenderButton);
diff --git a/src/insets/InsetExternal.h b/src/insets/InsetExternal.h
index 813e933a0a..c5f106cef5 100644
--- a/src/insets/InsetExternal.h
+++ b/src/insets/InsetExternal.h
@@ -110,7 +110,7 @@ public:
 	///
 	void setParams(InsetExternalParams const &);
 	/// Update not loaded previews
-	void updatePreview();
+	void updatePreview() const;
 	/// \returns the number of rows (\n's) of generated code.
 	void latex(otexstream &, OutputParams const &) const;
 	///
@@ -165,11 +165,15 @@ private:
 	 *  and the preview should be regenerated.
 	 */
 	void fileChanged() const;
+	/// Is this inset using (instant or graphics) preview?
+	bool isPreviewed() const;
+	/// Do we have the right renderer (button, graphic or monitored preview)?
+	bool isRendererValid() const;
 
 	/// The current params
 	InsetExternalParams params_;
 	/// The thing that actually draws the image on LyX's screen.
-	boost::scoped_ptr<RenderBase> renderer_;
+	mutable boost::scoped_ptr<RenderBase> renderer_;
 	/// changes color of the button when mouse enters/leaves this inset
 	mutable std::map<BufferView const *, bool> mouse_hover_;
 };
diff --git a/status.22x b/status.22x
index aac55fc5de..b5af1fea1d 100644
--- a/status.22x
+++ b/status.22x
@@ -100,6 +100,9 @@ What's new
 
 - Fix crash with undo and child documents (bug 10643).
 
+- Fix crash when changing preview preferences while previewable
+  external inset is open (bug 10785).
+
 - Remove duplicate entries from the Symbols dialog (bug 10644).
 
 - Always show the float type in the float inset label (bug 10618).