Color by selection mapping (#186)

alxvth · Sreeparna Deb · commit 8a7f8ec8425d · 2025-10-03T14:55:44.000+02:00
* WIP: color by selection mapping

* Add explanations

* Delay check

* Better be safe

* Add Reverse mapping as well

* Fix false parent

* Move new functions to own file

* Centralize &amp; inline check

* Simpler return types and checks

* Single swap

* WIP: map means to HSNE embedding

* Fix mapping from source of position to color by linked data

* Remove debug prints

* Delay surjection check for faster UI response
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -40,6 +40,8 @@ find_package(ManiVault COMPONENTS Core PointData ClusterData ColorData ImageData
 set(PLUGIN
     src/ScatterplotPlugin.h
     src/ScatterplotPlugin.cpp
+    src/MappingUtils.h
+    src/MappingUtils.cpp
 )
 
 set(UI
diff --git a/src/MappingUtils.cpp b/src/MappingUtils.cpp
@@ -0,0 +1,109 @@
+#include "MappingUtils.h"
+
+#include <Dataset.h>
+#include <LinkedData.h>
+#include <PointData/PointData.h>
+#include <Set.h>
+
+#include <algorithm>
+#include <cstdint>
+#include <functional>
+#include <map>
+#include <tuple>
+#include <ranges>
+#include <utility>
+#include <vector>
+
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMapping(const mv::Dataset<Points>& source, const mv::Dataset<Points>& target, LinkedDataCondition checkMapping) {
+    const std::vector<mv::LinkedData>& linkedDatas = source->getLinkedData();
+
+    if (linkedDatas.empty())
+        return { nullptr, 0 } ;
+
+    // find linked data between source and target OR source and target's parent, if target is derived and they have the same number of points
+    if (const auto result = std::ranges::find_if(
+            linkedDatas, 
+            [&target, &checkMapping](const mv::LinkedData& linkedData) -> bool {
+                return checkMapping(linkedData, target);
+            });
+        result != linkedDatas.end()) 
+    {
+        return {&(*result), target->getNumPoints() };
+    }
+
+    return { nullptr, 0 };
+}
+
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMappingColorsToPositions(const mv::Dataset<Points>& colors, const mv::Dataset<Points>& positions) {
+    auto testTargetAndParent = [](const mv::LinkedData& linkedData, const mv::Dataset<Points>& positions) -> bool {
+        const mv::Dataset<mv::DatasetImpl> mapTargetData = linkedData.getTargetDataset();
+        return mapTargetData == positions || parentHasSameNumPoints(mapTargetData, positions);
+        };
+
+    return getSelectionMapping(colors, positions, testTargetAndParent);
+}
+
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMappingPositionsToColors(const mv::Dataset<Points>& positions, const mv::Dataset<Points>& colors) {
+    auto testTarget = [](const mv::LinkedData& linkedData, const mv::Dataset<Points>& colors) -> bool {
+        return linkedData.getTargetDataset() == colors;
+        };
+
+    auto [mapping, numTargetPoints] = getSelectionMapping(positions, colors, testTarget);
+
+    if (mapping && parentHasSameNumPoints(positions, positions)) {
+        const auto positionsParent = positions->getParent<Points>();
+        std::tie(mapping, numTargetPoints) = getSelectionMapping(positionsParent, colors, testTarget);
+    }
+
+    return { mapping, numTargetPoints };
+}
+
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMappingPositionSourceToColors(const mv::Dataset<Points>& positions, const mv::Dataset<Points>& colors) {
+    if (!positions->isDerivedData())
+        return { nullptr, 0 };
+
+    const auto fullSourceData = positions->getSourceDataset<Points>()->getFullDataset<Points>();
+
+    if(!fullSourceData.isValid())
+        return { nullptr, 0 };
+
+    return getSelectionMappingPositionsToColors(fullSourceData, colors);
+}
+
+bool checkSurjectiveMapping(const mv::LinkedData& linkedData, const std::uint32_t numPointsInTarget) {
+    const std::map<std::uint32_t, std::vector<std::uint32_t>>& linkedMap = linkedData.getMapping().getMap();
+
+    std::vector<bool> found(numPointsInTarget, false);
+    std::uint32_t count = 0;
+
+    for (const auto& [key, vec] : linkedMap) {
+        for (std::uint32_t val : vec) {
+            if (val >= numPointsInTarget) continue; // Skip values that are too large
+
+            if (!found[val]) {
+                found[val] = true;
+                if (++count == numPointsInTarget)
+                    return true;
+            }
+        }
+    }
+
+    return false; // The previous loop would have returned early if the entire taget set was covered
+}
+
+bool checkSelectionMapping(const mv::Dataset<Points>& colors, const mv::Dataset<Points>& positions) {
+
+    // Check if there is a mapping
+    auto [mapping, numTargetPoints] = getSelectionMappingColorsToPositions(colors, positions);
+
+    if (!mapping)
+        std::tie(mapping, numTargetPoints) = getSelectionMappingPositionsToColors(positions, colors);
+
+    if (!mapping)
+        std::tie(mapping, numTargetPoints) = getSelectionMappingPositionSourceToColors(positions, colors);
+
+    if (!mapping)
+        return false;
+
+    return true;
+}
diff --git a/src/MappingUtils.h b/src/MappingUtils.h
@@ -0,0 +1,59 @@
+#pragma once
+
+#include <Dataset.h>
+#include <LinkedData.h>
+#include <PointData/PointData.h>
+#include <Set.h>
+
+#include <cstdint>
+#include <functional>
+#include <utility>
+
+// This only checks the immedeate parent and is deliberately not recursive
+// We might consider the latter in the future, but might need to cover edge cases
+inline bool parentHasSameNumPoints(const mv::Dataset<mv::DatasetImpl> data, const mv::Dataset<Points>& other) {
+    if (!data->isDerivedData())
+        return false;
+
+    const auto parent = data->getParent();
+    if (parent->getDataType() != PointType)
+        return false;
+
+    const auto parentPoints = mv::Dataset<Points>(parent);
+    return parentPoints->getNumPoints() == other->getNumPoints();
+}
+
+// Is the data derived and does it's full source data have same number of points as the other data
+inline bool fullSourceHasSameNumPoints(const mv::Dataset<mv::DatasetImpl> data, const mv::Dataset<Points>& other) {
+    if (!data->isDerivedData())
+        return false;
+
+    return data->getSourceDataset<Points>()->getFullDataset<Points>()->getNumPoints() == other->getNumPoints();
+}
+
+using LinkedDataCondition = std::function<bool(const mv::LinkedData& linkedData, const mv::Dataset<Points>& target)>;
+
+/*  Returns a mapping (linked data) from source that fulfils a given condition based on target, e.g.
+    auto checkMapping = [](const mv::LinkedData& linkedData, const mv::Dataset<Points>& target) -> bool {
+        return linkedData.getTargetDataset() == target;
+        };
+    This function will return the first match of the condition
+*/
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMapping(const mv::Dataset<Points>& source, const mv::Dataset<Points>& target, LinkedDataCondition checkMapping);
+
+// Returns a mapping (linked data) from colors whose target is positions or whose target's parent has the same number of points as positions
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMappingColorsToPositions(const mv::Dataset<Points>& colors, const mv::Dataset<Points>& positions);
+
+// Returns a mapping (linked data) from positions whose target is colors or 
+//  a mapping from positions' parent whose target is colors if the number of data points match 
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMappingPositionsToColors(const mv::Dataset<Points>& positions, const mv::Dataset<Points>& colors);
+
+// Returns a mapping (linked data) from positions' source data whose target is colors 
+std::pair<const mv::LinkedData*, unsigned int> getSelectionMappingPositionSourceToColors(const mv::Dataset<Points>& positions, const mv::Dataset<Points>& colors);
+
+// Check if the mapping is surjective, i.e. hits all elements in the target
+bool checkSurjectiveMapping(const mv::LinkedData& linkedData, const std::uint32_t numPointsInTarget);
+
+// returns whether there is a selection map from colors to positions or positions to colors (or respective parents)
+// checks whether the mapping covers all elements in the target
+bool checkSelectionMapping(const mv::Dataset<Points>& colors, const mv::Dataset<Points>& positions);
diff --git a/src/ScatterplotPlugin.cpp b/src/ScatterplotPlugin.cpp
@@ -1,5 +1,6 @@
 #include "ScatterplotPlugin.h"
 
+#include "MappingUtils.h"
 #include "ScatterplotWidget.h"
 
 #include <Application.h>
@@ -31,6 +32,9 @@
 
 #include <algorithm>
 #include <cassert>
+#include <exception>
+#include <map>
+#include <stdexcept>
 #include <vector>
 
 #define VIEW_SAMPLING_HTML
@@ -172,25 +176,35 @@ ScatterplotPlugin::ScatterplotPlugin(const PluginFactory* factory) :
                         });
                 }
 
-                // Accept both data with the same number if points and data which is derived from
-                // a parent that has the same number of points (e.g. for HSNE embeddings)
+                // Accept for recoloring:
+                //  1. data with the same number of points
+                //  2. data which is derived from a parent that has the same number of points (e.g. for HSNE embeddings), where we can use global indices for mapping
+                //  3. data which has a fully-covering selection mapping, that we can use for setting colors. Mapping in order of preference:
+                //      a) from color (or it's parent) to position
+                //      b) from color to position (or it's parent)
+                //      c) from source of position to color
+
+                // [1. Same number of points]
                 const auto numPointsCandidate   = candidateDataset->getNumPoints();
                 const auto numPointsPosition    = _positionDataset->getNumPoints();
-                const bool sameNumPoints        = numPointsPosition == numPointsCandidate;
-                const bool sameNumPointsAsFull  = 
-                    /*if*/   _positionDataset->isDerivedData() ?
-                    /*then*/ _positionDataset->getSourceDataset<Points>()->getFullDataset<Points>()->getNumPoints() == numPointsCandidate :
-                    /*else*/ false;
+                const bool hasSameNumPoints     = numPointsPosition == numPointsCandidate;
+
+                // [2. Derived from a parent]
+                const bool hasSameNumPointsAsFull = fullSourceHasSameNumPoints(_positionDataset, candidateDataset);
 
-                if (sameNumPoints || sameNumPointsAsFull) {
+                // [3. Full selection mapping]
+                const bool hasSelectionMapping  = checkSelectionMapping(candidateDataset, _positionDataset);
+
+                if (hasSameNumPoints || hasSameNumPointsAsFull || hasSelectionMapping) {
                     // Offer the option to use the points dataset as source for points colors
                     dropRegions << new DropWidget::DropRegion(this, "Point color", QString("Colorize %1 points with %2").arg(_positionDataset->text(), candidateDataset->text()), "palette", true, [this, candidateDataset]() {
                         _settingsAction.getColoringAction().setCurrentColorDataset(candidateDataset);   // calls addColorDataset internally
                         });
 
                 }
 
-                if (sameNumPoints) {
+                // Accept for resizing and opacity: Only data with the same number of points
+                if (hasSameNumPoints) {
                     // Offer the option to use the points dataset as source for points size
                     dropRegions << new DropWidget::DropRegion(this, "Point size", QString("Size %1 points with %2").arg(_positionDataset->text(), candidateDataset->text()), "ruler-horizontal", true, [this, candidateDataset]() {
                         _settingsAction.getPlotAction().getPointPlotAction().setCurrentPointSizeDataset(candidateDataset);
@@ -647,49 +661,125 @@ void ScatterplotPlugin::positionDatasetChanged()
     updateData();
 }
 
-void ScatterplotPlugin::loadColors(const Dataset<Points>& points, const std::uint32_t& dimensionIndex)
+void ScatterplotPlugin::loadColors(const Dataset<Points>& pointsColor, const std::uint32_t& dimensionIndex)
 {
     // Only proceed with valid points dataset
-    if (!points.isValid())
+    if (!pointsColor.isValid())
         return;
 
-    // Generate point scalars for color mapping
-    std::vector<float> scalars;
+    const auto numColorPoints = pointsColor->getNumPoints();
 
-    points->extractDataForDimension(scalars, dimensionIndex);
+    // Generate point colorScalars for color mapping
+    std::vector<float> colorScalars = {};
+    pointsColor->extractDataForDimension(colorScalars, dimensionIndex);
 
-    const auto numColorPoints = points->getNumPoints();
+    // If number of points do not match, use a mapping
+    // prefer global IDs (for derived data) over selection mapping
+    // prefer color to position over position to color over source of position to color
+    if (numColorPoints != _numPoints) {
 
+        std::vector<float> mappedColorScalars(_numPoints, std::numeric_limits<float>::lowest());
 
-    if (numColorPoints != _numPoints) {
+        try {
+            const bool hasSameNumPointsAsFull = fullSourceHasSameNumPoints(_positionDataset, pointsColor);
 
-        const bool sameNumPointsAsFull =
-            /*if*/   _positionDataset->isDerivedData() ?
-            /*then*/ _positionSourceDataset->getFullDataset<Points>()->getNumPoints() == numColorPoints :
-            /*else*/ false;
+            if (hasSameNumPointsAsFull) {
+                std::vector<std::uint32_t> globalIndices = {};
+                _positionDataset->getGlobalIndices(globalIndices);
 
-        if (sameNumPointsAsFull) {
-            std::vector<std::uint32_t> globalIndices;
-            _positionDataset->getGlobalIndices(globalIndices);
+                for (std::int32_t localIndex = 0; localIndex < globalIndices.size(); localIndex++) {
+                    mappedColorScalars[localIndex] = colorScalars[globalIndices[localIndex]];
+                }
 
-            std::vector<float> localScalars(_numPoints, 0);
-            std::int32_t localColorIndex = 0;
+            }
+            else if ( // mapping from color data set to position data set
+                const auto [selectionMapping, numPointsTarget] = getSelectionMappingColorsToPositions(pointsColor, _positionDataset);
+                /* check if valid */ 
+                selectionMapping != nullptr && 
+                numPointsTarget == _numPoints &&
+                checkSurjectiveMapping(*selectionMapping, numPointsTarget)
+                )
+            {
+                // Map values like selection
+                const mv::SelectionMap::Map& mapColorsToPositions = selectionMapping->getMapping().getMap();
 
-            for (const auto& globalIndex : globalIndices)
-                localScalars[localColorIndex++] = scalars[globalIndex];
+                for (const auto& [fromColorID, vecOfPositionIDs] : mapColorsToPositions) {
+                    for (std::uint32_t toPositionID : vecOfPositionIDs) {
+                        mappedColorScalars[toPositionID] = colorScalars[fromColorID];
+                    }
+                }
 
-            std::swap(localScalars, scalars);
-           }
-        else {
-            qWarning("Number of points used for coloring does not match number of points in data, aborting attempt to color plot");
+            }
+            else if ( // mapping from position data set to color data set 
+                const auto [selectionMapping, numPointsTarget] = getSelectionMappingPositionsToColors(_positionDataset, pointsColor);
+                /* check if valid */ 
+                selectionMapping != nullptr &&
+                numPointsTarget == numColorPoints &&
+                checkSurjectiveMapping(*selectionMapping, numPointsTarget)
+                )
+            {
+                // Map values like selection (in reverse, use first value that occurs)
+                const mv::SelectionMap::Map& mapPositionsToColors = selectionMapping->getMapping().getMap();
+
+                for (const auto& [fromPositionID, vecOfColorIDs] : mapPositionsToColors) {
+                    if (mappedColorScalars[fromPositionID] != std::numeric_limits<float>::lowest())
+                        continue;
+                    for (std::uint32_t toColorID : vecOfColorIDs) {
+                        mappedColorScalars[fromPositionID] = colorScalars[toColorID];
+                    }
+                }
+
+            }
+            else if ( // mapping from source of position data set to color data set 
+                const auto [selectionMapping, numPointsTarget] = getSelectionMappingPositionSourceToColors(_positionDataset, pointsColor);
+                /* check if valid */ 
+                selectionMapping != nullptr && 
+                numPointsTarget == numColorPoints &&
+                checkSurjectiveMapping(*selectionMapping, numPointsTarget)
+                )
+            {
+                // the selection map is from full source data of positions data to pointsColor
+                // we need to use both the global indices of the positions (i.e. in the source) and the linked data mapping
+                const mv::SelectionMap::Map& mapGlobalToColors = selectionMapping->getMapping().getMap();
+                std::vector<std::uint32_t> globalIndices = {};
+                _positionDataset->getGlobalIndices(globalIndices);
+
+                for (std::int32_t localIndex = 0; localIndex < globalIndices.size(); localIndex++) {
+
+                    if (mappedColorScalars[localIndex] != std::numeric_limits<float>::lowest())
+                        continue;
+
+                    const auto& indxColors = mapGlobalToColors.at(globalIndices[localIndex]);   // from full source (parent) to colorDataset
+
+                    for (const auto& indColors : indxColors) {
+                        mappedColorScalars[localIndex] = colorScalars[indColors];
+                    }
+                }
+
+            }
+            else {
+                throw std::runtime_error("Coloring data set does not match position data set in a known way, aborting attempt to color plot");
+            }
+
+        }
+        catch (const std::exception& e) {
+            qDebug() << "ScatterplotPlugin::loadColors: mapping failed -> " << e.what();
+            _settingsAction.getColoringAction().getColorByAction().setCurrentIndex(0);  // reset to color by constant
             return;
         }
+        catch (...) {
+            qDebug() << "ScatterplotPlugin::loadColors: mapping failed for an unknown reason.";
+            _settingsAction.getColoringAction().getColorByAction().setCurrentIndex(0);  // reset to color by constant
+            return;
+        }
+
+        std::swap(mappedColorScalars, colorScalars);
     }
 
-    assert(scalars.size() == _numPoints);
+    assert(colorScalars.size() == _numPoints);
 
-    // Assign scalars and scalar effect
-    _scatterPlotWidget->setScalars(scalars);
+    // Assign colorScalars and scalar effect
+    _scatterPlotWidget->setScalars(colorScalars);
     _scatterPlotWidget->setScalarEffect(PointEffect::Color);
 
     _settingsAction.getColoringAction().updateColorMapActionScalarRange();

Original file line number	Diff line number	Diff line change
`@@ -40,6 +40,8 @@ find_package(ManiVault COMPONENTS Core PointData ClusterData ColorData ImageData`
`40`	`40`	`set(PLUGIN`
`41`	`41`	`src/ScatterplotPlugin.h`
`42`	`42`	`src/ScatterplotPlugin.cpp`
	`43`	`+ src/MappingUtils.h`
	`44`	`+ src/MappingUtils.cpp`
`43`	`45`	`)`
`44`	`46`
`45`	`47`	`set(UI`