From: Soeren Apel <redacted>
Date: Wed, 30 Dec 2015 17:34:47 +0000 (+0100)
Subject: DecodeTrace: Prevent trace height from jumping
X-Git-Tag: pulseview-0.3.0~12
X-Git-Url: https://sigrok.org/gitweb/?p=pulseview.git;a=commitdiff_plain;h=eee89ff865c28854eebdcecbe344f225b9ee366f

DecodeTrace: Prevent trace height from jumping

In 506317984393a41000650ccca868f3dd66872a4f, the decode
trace height was made dependent on the number of currently
visible annotation rows.
This however has issues: when zooming in on an area where
there are no annotations, the height of the decode trace
collapses. With this patch, this can't happen anymore as
a new variable keeps track of the maximum number of
annotation rows ever encountered, keeping the decoder
trace height stable.
---

diff --git a/pv/view/decodetrace.cpp b/pv/view/decodetrace.cpp
index 2e16ff96..f2aadd1b 100644
--- a/pv/view/decodetrace.cpp
+++ b/pv/view/decodetrace.cpp
@@ -133,6 +133,7 @@ DecodeTrace::DecodeTrace(pv::Session &session,
 	session_(session),
 	decoder_stack_(decoder_stack),
 	row_height_(0),
+	max_visible_rows_(0),
 	delete_mapper_(this),
 	show_hide_mapper_(this)
 {
@@ -161,9 +162,8 @@ const std::shared_ptr<pv::data::DecoderStack>& DecodeTrace::decoder() const
 pair<int, int> DecodeTrace::v_extents() const
 {
 	const int row_height = (ViewItemPaintParams::text_height() * 6) / 4;
-	const int rows = visible_rows_.size();
 
-	return make_pair(-row_height, row_height * rows);
+	return make_pair(-row_height, row_height * max_visible_rows_);
 }
 
 void DecodeTrace::paint_back(QPainter &p, const ViewItemPaintParams &pp)
@@ -222,6 +222,9 @@ void DecodeTrace::paint_mid(QPainter &p, const ViewItemPaintParams &pp)
 
 	// Draw the hatching
 	draw_unresolved_period(p, annotation_height, pp.left(), pp.right());
+
+	// Update the maximum row count if needed
+	max_visible_rows_ = std::max(max_visible_rows_, (int)visible_rows_.size());
 }
 
 void DecodeTrace::paint_fore(QPainter &p, const ViewItemPaintParams &pp)
diff --git a/pv/view/decodetrace.hpp b/pv/view/decodetrace.hpp
index 92544ae2..4964a95d 100644
--- a/pv/view/decodetrace.hpp
+++ b/pv/view/decodetrace.hpp
@@ -206,7 +206,7 @@ private:
 	std::vector<pv::widgets::DecoderGroupBox*> decoder_forms_;
 
 	std::vector<data::decode::Row> visible_rows_;
-	int row_height_;
+	int row_height_, max_visible_rows_;
 
 	QSignalMapper delete_mapper_, show_hide_mapper_;
 };