Display message when trying to drag/drop a scalar into a waveform view to make it more obvious why this won't work

Author: azonenberg

release-notes/CHANGELOG.md

@@ -7,7 +7,7 @@ This is a running list of significant bug fixes and new features since the last
 * Core: Changed rate limiting sleep in InstrumentThread loop from 10ms to 1ms to avoid bogging down high performance instruments like the ThunderScope
 * Drivers: ThunderScope now overlaps socket IO and GPU processing of waveforms giving a significant increase in WFM/s rate
 * Filters: Added GPU acceleration for several filters including CDR PLL (7.5x speedup), 100baseTX (10x speedup), eye pattern (25x speedup), histogram (12x speedup), TIE (5.3x speedup) and more (https://github.com/ngscopeclient/scopehal/issues/977).
-* Filters: CDR PLL now outputs the input signal sampled by the recovered clock in a second data stream.
+* Filters: CDR PLL now outputs the input signal sampled by the recovered clock in a second data stream (https://github.com/ngscopeclient/scopehal/issues/991)
 * Filters: Peak detector for FFT etc now does quadratic interpolation for sub-sample peak fitting
 * Filters: Horizontal bathtub curve now works properly with MLT-3 / PAM-3 eyes as well as NRZ. No PAM-4 or higher support yet.
 * Filters: PcapNG export now has an additional mode selector for use with named pipes, allowing live streaming of PcapNG formatted data to WireShark
@@ -28,3 +28,5 @@ We try to maintain compatibility with older versions of ngscopeclient but occasi
 * GUI: Pressing middle mouse on the Y axis to autoscale would fail, setting the full scale range to zero volts, if the waveform was resident in GPU memory and the CPU-side copy of the buffer was stale
 
 ## Other changes since v0.1.1
+
+* General UI overhaul of stream browser to make things more intuitive and reduce the number of clicks needed to perform common tasks

src/ngscopeclient/MainWindow.cpp

@@ -2,7 +2,7 @@
 *                                                                                                                      *
 * ngscopeclient                                                                                                        *
 *                                                                                                                      *
-* Copyright (c) 2012-2025 Andrew D. Zonenberg and contributors                                                         *
+* Copyright (c) 2012-2026 Andrew D. Zonenberg and contributors                                                         *
 * All rights reserved.                                                                                                 *
 *                                                                                                                      *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the     *
@@ -171,9 +171,7 @@ MainWindow::MainWindow(shared_ptr<QueueHandle> queue)
 	m_toolbarIconSize = 0;
 	LoadToolbarIcons();
 	LoadGradients();
-	m_texmgr.LoadTexture("warning", FindDataFile("icons/48x48/dialog-warning-2.png"));
-	m_texmgr.LoadTexture("visible-spectrum-380nm-750nm",
-		FindDataFile("icons/gradients/visible-spectrum-380nm-750nm.png"));
+	LoadMiscIcons();
 	LoadFilterIcons();
 	LoadStatusBarIcons();
 	LoadWaveformShapeIcons();

src/ngscopeclient/MainWindow.h

@@ -2,7 +2,7 @@
 *                                                                                                                      *
 * ngscopeclient                                                                                                        *
 *                                                                                                                      *
-* Copyright (c) 2012-2025 Andrew D. Zonenberg and contributors                                                         *
+* Copyright (c) 2012-2026 Andrew D. Zonenberg and contributors                                                         *
 * All rights reserved.                                                                                                 *
 *                                                                                                                      *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the     *
@@ -130,7 +130,7 @@ class MainWindow : public VulkanWindow
 	{ m_splitRequests.push_back(SplitGroupRequest(group, direction, stream)); }
 
 	void ShowChannelProperties(OscilloscopeChannel* channel);
-	void ShowInstrumentProperties(std::shared_ptr<Instrument> instrumet);
+	void ShowInstrumentProperties(std::shared_ptr<Instrument> instrument);
 	void ShowTriggerProperties();
 	void ShowManageInstruments();
 	void ShowSyncWizard(std::shared_ptr<TriggerGroup> group, std::shared_ptr<Oscilloscope> secondary);
@@ -275,6 +275,7 @@ class MainWindow : public VulkanWindow
 	std::vector<std::string> m_eyeGradients;
 
 	void LoadFilterIcons();
+	void LoadMiscIcons();
 	void LoadStatusBarIcons();
 	void LoadWaveformShapeIcons();
 	void LoadAppIcon();

src/ngscopeclient/MainWindow_Icons.cpp

@@ -2,7 +2,7 @@
 *                                                                                                                      *
 * ngscopeclient                                                                                                        *
 *                                                                                                                      *
-* Copyright (c) 2012-2025 Andrew D. Zonenberg and contributors                                                         *
+* Copyright (c) 2012-2026 Andrew D. Zonenberg and contributors                                                         *
 * All rights reserved.                                                                                                 *
 *                                                                                                                      *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the     *
@@ -793,6 +793,17 @@ string MainWindow::GetIconForWaveformShape(FunctionGenerator::WaveShape shape)
 	return "shape-default";
 }
 
+/**
+	@brief Load various miscellaneous icons and textures
+ */
+void MainWindow::LoadMiscIcons()
+{
+	m_texmgr.LoadTexture("warning", FindDataFile("icons/48x48/dialog-warning-2.png"));
+	m_texmgr.LoadTexture("info", FindDataFile("icons/48x48/dialog-information-3.png"));
+	m_texmgr.LoadTexture("visible-spectrum-380nm-750nm",
+		FindDataFile("icons/gradients/visible-spectrum-380nm-750nm.png"));
+}
+
 /**
 	@brief Load toolbar icons from disk if preferences changed
  */

src/ngscopeclient/StreamBrowserDialog.cpp

@@ -2,7 +2,7 @@
 *                                                                                                                      *
 * ngscopeclient                                                                                                        *
 *                                                                                                                      *
-* Copyright (c) 2012-2025 Andrew D. Zonenberg and contributors                                                         *
+* Copyright (c) 2012-2026 Andrew D. Zonenberg and contributors                                                         *
 * All rights reserved.                                                                                                 *
 *                                                                                                                      *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the     *
@@ -1259,11 +1259,9 @@ void StreamBrowserDialog::renderChannelNode(shared_ptr<Instrument> instrument, s
 	auto psuchan = dynamic_cast<PowerSupplyChannel *>(channel);
 	auto awgchan = dynamic_cast<FunctionGeneratorChannel *>(channel);
 	bool renderProps = false;
-	bool isDigital = false;
 	if (scopechan)
 	{
 		renderProps = scopechan->IsEnabled();
-		isDigital = scopechan->GetType(0) == Stream::STREAM_TYPE_DIGITAL;
 	}
 	else if(awg && awgchan)
 	{
@@ -1278,20 +1276,33 @@ void StreamBrowserDialog::renderChannelNode(shared_ptr<Instrument> instrument, s
 	int flags = 0;
 	if(!hasChildren)
 		flags |= ImGuiTreeNodeFlags_Leaf;
-
-	//Collapse all scope channel nodes by default to reduce clutter
-	if(isDigital || scopechan)
-	{}
-
 	else
-		flags |= ImGuiTreeNodeFlags_DefaultOpen;
+		flags |= ImGuiTreeNodeFlags_OpenOnArrow;
 
 	bool open = ImGui::TreeNodeEx(
 		channel->GetDisplayName().c_str(),
 		flags);
 	if (channel->m_displaycolor != "")
 		ImGui::PopStyleColor();
 
+	//Open properties dialog on double click
+	if(ImGui::IsItemHovered())
+	{
+		if(ImGui::IsMouseDoubleClicked(ImGuiMouseButton_Left))
+		{
+			if(scopechan)
+				m_parent->ShowChannelProperties(scopechan);
+			else if(psuchan)
+				m_parent->ShowInstrumentProperties(psu);
+			else if(awgchan)
+				m_parent->ShowInstrumentProperties(awg);
+			else
+				LogWarning("Don't know how to open channel properties yet\n");
+		}
+
+		m_parent->AddStatusHelp("mouse_lmb_double", "Open properties");
+	}
+
 	//Single stream: drag the stream not the channel
 	if(singleStream)
 	{
@@ -1418,7 +1429,7 @@ void StreamBrowserDialog::renderChannelNode(shared_ptr<Instrument> instrument, s
 			for(size_t j=0; j<streamCount; j++)
 			{
 				// Iterate on each stream
-				renderStreamNode(instrument,channel,j,!singleStream,renderProps,(j==(streamCount-1)));
+				renderStreamNode(instrument,channel,j,!singleStream,renderProps);
 			}
 		}
 		ImGui::PopID();
@@ -1438,9 +1449,8 @@ void StreamBrowserDialog::renderChannelNode(shared_ptr<Instrument> instrument, s
    @param streamIndex the index of the stream to render
    @param renderName true if the name of the stream should be rendred as a selectable item
    @param renderProps true if a properties block should be rendered for this stream
-   @param isLast true if this is the last stream of the channel
  */
-void StreamBrowserDialog::renderStreamNode(shared_ptr<Instrument> instrument, InstrumentChannel* channel, size_t streamIndex, bool renderName, bool renderProps, bool isLast)
+void StreamBrowserDialog::renderStreamNode(shared_ptr<Instrument> instrument, InstrumentChannel* channel, size_t streamIndex, bool renderName, bool renderProps)
 {
 	auto scope = std::dynamic_pointer_cast<Oscilloscope>(instrument);
 	auto scopechan = dynamic_cast<OscilloscopeChannel *>(channel);
@@ -1452,7 +1462,6 @@ void StreamBrowserDialog::renderStreamNode(shared_ptr<Instrument> instrument, In
 	if (renderName)
 	{
 		ImGui::Selectable(channel->GetStreamName(streamIndex).c_str());
-
 		StreamDescriptor s(channel, streamIndex);
 		if(ImGui::BeginDragDropSource())
 		{
@@ -1475,8 +1484,7 @@ void StreamBrowserDialog::renderStreamNode(shared_ptr<Instrument> instrument, In
 	// Channel/stream properties block
 	if(renderProps && scopechan)
 	{
-		// If no properties are available for this stream, only show a "Properties" link if it is the last stream of the channel/filter
-		bool hasProps = isLast;
+		bool hasProps = false;
 		switch (type)
 		{
 			case Stream::STREAM_TYPE_ANALOG:
@@ -1497,8 +1505,8 @@ void StreamBrowserDialog::renderStreamNode(shared_ptr<Instrument> instrument, In
 				ImGuiChildFlags_AutoResizeY | ImGuiChildFlags_Borders);
 
 			Unit unit = channel->GetYAxisUnits(streamIndex);
-			bool clicked = false;
-			bool hovered = false;
+			bool clicked;
+			bool hovered;
 			switch (type)
 			{
 				case Stream::STREAM_TYPE_ANALOG:
@@ -1519,18 +1527,10 @@ void StreamBrowserDialog::renderStreamNode(shared_ptr<Instrument> instrument, In
 					//fall through
 				default:
 					{
-						clicked = ImGui::TextLink("Properties");
-						hovered = ImGui::IsItemHovered();
 					}
 					break;
 			}
 			ImGui::EndChild();
-			if (clicked)
-			{
-				m_parent->ShowChannelProperties(scopechan);
-			}
-			if (hovered)
-				m_parent->AddStatusHelp("mouse_lmb", "Open properties");
 		}
 	}
 	ImGui::PopID();
@@ -1551,14 +1551,22 @@ void StreamBrowserDialog::renderFilterNode(Filter* filter)
 		ImGui::PushStyleColor(ImGuiCol_Text, ColorFromString(filter->m_displaycolor));
 
 	//Don't expand filters with a single stream by default
-	int flags = 0;
+	int flags = ImGuiTreeNodeFlags_OpenOnArrow;
 	if(!singleStream)
 		flags |= ImGuiTreeNodeFlags_DefaultOpen;
 
 	bool open = ImGui::TreeNodeEx(filter->GetDisplayName().c_str(), flags);
 	if (filter->m_displaycolor != "")
 		ImGui::PopStyleColor();
 
+	//Open properties dialog on double click
+	if(ImGui::IsItemHovered())
+	{
+		if(ImGui::IsMouseDoubleClicked(ImGuiMouseButton_Left))
+			m_parent->ShowChannelProperties(filter);
+		m_parent->AddStatusHelp("mouse_lmb_double", "Open properties");
+	}
+
 	//Single stream: drag the stream not the filter
 	if(singleStream)
 	{
@@ -1593,10 +1601,8 @@ void StreamBrowserDialog::renderFilterNode(Filter* filter)
 
 		size_t streamCount = filter->GetStreamCount();
 		for(size_t j=0; j<streamCount; j++)
-		{
-			// Iterate on each stream
-			renderStreamNode(nullptr,filter,j,!singleStream,true,(j==(streamCount-1)));
-		}
+			renderStreamNode(nullptr,filter,j,!singleStream,true);
+
 		ImGui::PopID();
 	}
 

src/ngscopeclient/StreamBrowserDialog.h

@@ -2,7 +2,7 @@
 *                                                                                                                      *
 * ngscopeclient                                                                                                        *
 *                                                                                                                      *
-* Copyright (c) 2012-2025 Andrew D. Zonenberg and contributors                                                         *
+* Copyright (c) 2012-2026 Andrew D. Zonenberg and contributors                                                         *
 * All rights reserved.                                                                                                 *
 *                                                                                                                      *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the     *
@@ -168,7 +168,7 @@ class StreamBrowserDialog : public Dialog
 	void renderChannelNode(std::shared_ptr<Instrument> instrument, size_t channelIndex, bool isLast);
 
 	// Rendering of a stream node
-	void renderStreamNode(std::shared_ptr<Instrument> instrument, InstrumentChannel* channel, size_t streamIndex, bool renderName, bool renderProps, bool isLast);
+	void renderStreamNode(std::shared_ptr<Instrument> instrument, InstrumentChannel* channel, size_t streamIndex, bool renderName, bool renderProps);
 
 	// Rendering of an Filter node
 	void renderFilterNode(Filter* filter);

src/ngscopeclient/WaveformArea.cpp

@@ -3313,6 +3313,25 @@ void WaveformArea::DragDropOverlays(ImVec2 start, ImVec2 size, int iArea, int nu
 	ImVec2 edgeSize(widthOfVerticalEdge, heightOfMiddle);
 	EdgeDropArea("left", ImVec2(start.x, topOfMiddle), edgeSize, ImGuiDir_Left);
 	EdgeDropArea("right", ImVec2(rightOfMiddle, topOfMiddle), edgeSize, ImGuiDir_Right);
+
+	//Cannot drop scalars into a waveform view. Make this a bit more obvious
+	auto payload = ImGui::GetDragDropPayload();
+	if(payload)
+	{
+		if(payload->IsDataType("Scalar"))
+		{
+			ImGui::SetCursorScreenPos(start);
+			ImGui::InvisibleButton("scalarDrop", size);
+			ImGui::SetNextItemAllowOverlap();
+
+			if(ImGui::IsItemHovered(ImGuiHoveredFlags_RectOnly))
+			{
+				DrawDropScalarMessage(
+					ImGui::GetWindowDrawList(),
+					ImVec2(start.x + size.x/4, start.y + size.y/2));
+			}
+		}
+	}
 }
 
 /**
@@ -3330,6 +3349,7 @@ void WaveformArea::EdgeDropArea(const string& name, ImVec2 start, ImVec2 size, I
 	auto payload = ImGui::GetDragDropPayload();
 	if(!payload)
 		return;
+
 	bool isWaveform = payload->IsDataType("Waveform");
 	bool isStream = payload->IsDataType("Stream");
 	if(!isWaveform && !isStream)
@@ -3650,6 +3670,42 @@ void WaveformArea::CenterRightDropArea(ImVec2 start, ImVec2 size)
 		rounding);
 }
 
+void WaveformArea::DrawDropScalarMessage(ImDrawList* list, ImVec2 center)
+{
+	float iconSize = ImGui::GetFontSize() * 3;
+
+	//Warning icon
+	list->AddImage(
+		m_parent->GetTextureManager()->GetTexture("info"),
+		ImVec2(center.x - 0.5, center.y - iconSize/2 - 0.5),
+		ImVec2(center.x + iconSize + 0.5, center.y + iconSize/2 + 0.5));
+
+	//Prepare to draw text
+	center.x += iconSize;
+	string str = "Cannot add a scalar value to a waveform view.\nTry dragging to the measurements window.";
+
+	//Draw background for text
+	float wrapWidth = 40 * ImGui::GetFontSize();
+	auto textsize = ImGui::CalcTextSize(str.c_str(), nullptr, false, wrapWidth);
+	float padding = 5;
+	float wrounding = 2;
+	list->AddRectFilled(
+		ImVec2(center.x, center.y - textsize.y/2 - padding),
+		ImVec2(center.x + textsize.x + 2*padding, center.y + textsize.y/2 + padding),
+		ImGui::GetColorU32(ImGuiCol_PopupBg),
+		wrounding);
+
+	//Draw the text
+	list->AddText(
+		ImGui::GetFont(),
+		ImGui::GetFontSize(),
+		ImVec2(center.x + padding, center.y - textsize.y/2),
+		ImGui::GetColorU32(ImGuiCol_Text),
+		str.c_str(),
+		nullptr,
+		wrapWidth);
+}
+
 /**
 	@brief Display a warning message about mismatched vertical scale
  */

src/ngscopeclient/WaveformArea.h

@@ -553,6 +553,8 @@ class WaveformArea : public SerializableObject
 		StreamDescriptor ourStream,
 		StreamDescriptor theirStream);
 
+	void DrawDropScalarMessage(ImDrawList* list, ImVec2 center);
+
 	void DragDropOverlays(ImVec2 start, ImVec2 size, int iArea, int numAreas);
 	void CenterLeftDropArea(ImVec2 start, ImVec2 size);
 	void CenterRightDropArea(ImVec2 start, ImVec2 size);

src/ngscopeclient/icons/48x48/dialog-information-3.png

@@ -3,3 +3,4 @@ EXCEPT for the following icons which are from the Open Icon Library and covered
 (details in OpenIconLibraryLicensing.txt):
 
 dialog-warning-2.png (public domain)
+dialog-information-3.png (CC-BY-SA 3.0 or LGPL)