# HG changeset patch
# User Chris Cannam
# Date 1571136056 -3600
# Node ID 4f8c72adbf434f5ab680a2ce459e1b5def1ed342
# Parent  5a215033b85387a141d162c18920c3152134af50
Clarify naming of some view-related methods. Rename LayerGeometryProvider::getValueExtents to getVisibleExtentsForUnit, and View::getTextLabelHeight to getTextLabelYCoord. Add View::getVisibleExtentsForAnyUnit to be used to determine which unit to adopt in a new e.g. box layer.

diff -r 5a215033b853 -r 4f8c72adbf43 layer/BoxLayer.cpp
--- a/layer/BoxLayer.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/BoxLayer.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -472,7 +472,7 @@
 
     if (m_verticalScale == AutoAlignScale) {
 
-        if (!v->getValueExtents(queryUnits, min, max, log)) {
+        if (!v->getVisibleExtentsForUnit(queryUnits, min, max, log)) {
 
             min = model->getValueMinimum();
             max = model->getValueMaximum();
diff -r 5a215033b853 -r 4f8c72adbf43 layer/FlexiNoteLayer.cpp
--- a/layer/FlexiNoteLayer.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/FlexiNoteLayer.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -675,7 +675,7 @@
 
     if (shouldAutoAlign()) {
 
-        if (!v->getValueExtents(queryUnits, min, max, log)) {
+        if (!v->getVisibleExtentsForUnit(queryUnits, min, max, log)) {
 
             auto model = ModelById::getAs<NoteModel>(m_model);
             min = model->getValueMinimum();
diff -r 5a215033b853 -r 4f8c72adbf43 layer/Layer.cpp
--- a/layer/Layer.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/Layer.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -630,7 +630,7 @@
         return false;
     }
 
-    if (!v->getValueExtents(unit, min, max, logarithmic)) {
+    if (!v->getVisibleExtentsForUnit(unit, min, max, logarithmic)) {
         return false;
     }
 
diff -r 5a215033b853 -r 4f8c72adbf43 layer/Layer.h
--- a/layer/Layer.h	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/Layer.h	Tue Oct 15 11:40:56 2019 +0100
@@ -457,18 +457,20 @@
      * these values if known.
      *
      * This function returns the "normal" extents for the layer, not
-     * necessarily the extents actually in use in the display.
+     * necessarily the extents actually in use in the display (see
+     * getDisplayExtents).
      */
     virtual bool getValueExtents(double &min, double &max,
                                  bool &logarithmic, QString &unit) const = 0;
 
     /**
-     * Return the minimum and maximum values within the displayed
-     * range for the y axis, if only a subset of the whole range of
-     * the model (returned by getValueExtents) is being displayed.
-     * Return false if the layer is not imposing a particular display
-     * extent (using the normal layer extents or deferring to whatever
-     * is in use for the same units elsewhere in the view).
+     * Return the minimum and maximum values within the visible area
+     * for the y axis of this layer.
+     *
+     * Return false if the layer has no display extents of its
+     * own. This could be because the layer is "auto-aligning" against
+     * another layer with the same units elsewhere in the view, or
+     * because the layer has no concept of a vertical scale at all.
      */
     virtual bool getDisplayExtents(double & /* min */,
                                    double & /* max */) const {
diff -r 5a215033b853 -r 4f8c72adbf43 layer/LayerGeometryProvider.h
--- a/layer/LayerGeometryProvider.h	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/LayerGeometryProvider.h	Tue Oct 15 11:40:56 2019 +0100
@@ -142,10 +142,32 @@
                                     double minFreq, double maxFreq,
                                     bool logarithmic) const = 0;
 
-    virtual int getTextLabelHeight(const Layer *layer, QPainter &) const = 0;
+    /**
+     * Return a y-coordinate at which text labels for individual items
+     * in a layer may be drawn, so as not to overlap with those of
+     * other layers. The returned coordinate will be near the top of
+     * the visible widget, but adjusted downward depending on how many
+     * other visible layers return true from their implementation of
+     * Layer::needsTextLabelHeight().
+     */
+    virtual int getTextLabelYCoord(const Layer *layer, QPainter &) const = 0;
 
-    virtual bool getValueExtents(QString unit, double &min, double &max,
-                                 bool &log) const = 0;
+    /**
+     * Return the visible vertical extents for the given unit, if any.
+     * That is:
+     * 
+     * - if at least one non-dormant layer uses the same unit and
+     *   returns some values from its getDisplayExtents() method,
+     *   return the extents from the topmost of those
+     *
+     * - otherwise, if at least one non-dormant layer uses the same
+     *   unit, return the union of the value extents of all of those
+     * 
+     * - otherwise return false
+     */
+    virtual bool getVisibleExtentsForUnit(QString unit,
+                                          double &min, double &max,
+                                          bool &log) const = 0;
 
     /**
      * Return the zoom level, i.e. the number of frames per pixel or
diff -r 5a215033b853 -r 4f8c72adbf43 layer/NoteLayer.cpp
--- a/layer/NoteLayer.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/NoteLayer.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -599,7 +599,7 @@
 
     if (shouldAutoAlign()) {
 
-        if (!v->getValueExtents(queryUnits, min, max, log)) {
+        if (!v->getVisibleExtentsForUnit(queryUnits, min, max, log)) {
 
             min = model->getValueMinimum();
             max = model->getValueMaximum();
diff -r 5a215033b853 -r 4f8c72adbf43 layer/RegionLayer.cpp
--- a/layer/RegionLayer.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/RegionLayer.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -608,7 +608,7 @@
 
     if (m_verticalScale == AutoAlignScale) {
 
-        if (!v->getValueExtents(queryUnits, min, max, log)) {
+        if (!v->getVisibleExtentsForUnit(queryUnits, min, max, log)) {
 
             min = model->getValueMinimum();
             max = model->getValueMaximum();
@@ -1027,7 +1027,7 @@
                     - paint.fontMetrics().descent();
             } else {
                 labelX = x + 5;
-                labelY = v->getTextLabelHeight(this, paint);
+                labelY = v->getTextLabelYCoord(this, paint);
                 if (labelX < nextLabelMinX) {
                     if (lastLabelY < v->getPaintHeight()/2) {
                         labelY = lastLabelY + fontHeight;
diff -r 5a215033b853 -r 4f8c72adbf43 layer/TimeInstantLayer.cpp
--- a/layer/TimeInstantLayer.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/TimeInstantLayer.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -378,7 +378,7 @@
     }
         
     int prevX = -1;
-    int textY = v->getTextLabelHeight(this, paint);
+    int textY = v->getTextLabelYCoord(this, paint);
     
     for (EventVector::const_iterator i = points.begin();
          i != points.end(); ++i) {
diff -r 5a215033b853 -r 4f8c72adbf43 layer/TimeValueLayer.cpp
--- a/layer/TimeValueLayer.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/layer/TimeValueLayer.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -781,7 +781,7 @@
 
     if (shouldAutoAlign()) {
 
-        if (!v->getValueExtents(getScaleUnits(), min, max, log)) {
+        if (!v->getVisibleExtentsForUnit(getScaleUnits(), min, max, log)) {
             min = model->getValueMinimum();
             max = model->getValueMaximum();
         } else if (log) {
@@ -968,7 +968,7 @@
 
     int textY = 0;
     if (m_plotStyle == PlotSegmentation) {
-        textY = v->getTextLabelHeight(this, paint);
+        textY = v->getTextLabelYCoord(this, paint);
     } else {
         int originY = getYForValue(v, 0.f);
         if (originY > 0 && originY < v->getPaintHeight()) {
diff -r 5a215033b853 -r 4f8c72adbf43 view/Pane.h
--- a/view/Pane.h	Tue Oct 15 09:32:24 2019 +0100
+++ b/view/Pane.h	Tue Oct 15 11:40:56 2019 +0100
@@ -106,10 +106,6 @@
     void mouseEnteredWidget();
     void mouseLeftWidget();
 
-    bool getTopLayerDisplayExtents(double &valueMin, double &valueMax,
-                                   double &displayMin, double &displayMax,
-                                   QString *unit = 0);
-
 protected slots:
     void playbackScheduleTimerElapsed();
 
@@ -154,6 +150,9 @@
 
     bool canTopLayerMoveVertical();
     bool setTopLayerDisplayExtents(double displayMin, double displayMax);
+    bool getTopLayerDisplayExtents(double &valueMin, double &valueMax,
+                                   double &displayMin, double &displayMax,
+                                   QString *unit = 0);
 
     void dragTopLayer(QMouseEvent *e);
     void dragExtendSelection(QMouseEvent *e);
diff -r 5a215033b853 -r 4f8c72adbf43 view/View.cpp
--- a/view/View.cpp	Tue Oct 15 09:32:24 2019 +0100
+++ b/view/View.cpp	Tue Oct 15 11:40:56 2019 +0100
@@ -193,44 +193,102 @@
 }
 
 bool
-View::getValueExtents(QString unit, double &min, double &max, bool &log) const
+View::getVisibleExtentsForUnit(QString unit,
+                               double &min, double &max,
+                               bool &log) const
 {
     bool have = false;
 
-    for (LayerList::const_iterator i = m_layerStack.begin();
-         i != m_layerStack.end(); ++i) { 
-
+    // Iterate in reverse order, so as to return display extents of
+    // topmost layer that fits the bill
+    
+    for (auto i = m_layerStack.rbegin(); i != m_layerStack.rend(); ++i) { 
+
+        Layer *layer = *i;
+
+        if (layer->isLayerDormant(this)) {
+            continue;
+        }
+        
         QString layerUnit;
         double layerMin = 0.0, layerMax = 0.0;
+        bool layerLog = false;
+
+        if (!layer->getValueExtents(layerMin, layerMax, layerLog, layerUnit)) {
+            continue;
+        }
+        if (layerUnit.toLower() != unit.toLower()) {
+            continue;
+        }
+
         double displayMin = 0.0, displayMax = 0.0;
-        bool layerLog = false;
-
-        if ((*i)->getValueExtents(layerMin, layerMax, layerLog, layerUnit) &&
-            layerUnit.toLower() == unit.toLower()) {
-
-            if ((*i)->getDisplayExtents(displayMin, displayMax)) {
-
-                min = displayMin;
-                max = displayMax;
-                log = layerLog;
-                have = true;
-                break;
-
-            } else {
-
-                if (!have || layerMin < min) min = layerMin;
-                if (!have || layerMax > max) max = layerMax;
-                if (layerLog) log = true;
-                have = true;
-            }
+        
+        if (layer->getDisplayExtents(displayMin, displayMax)) {
+
+            min = displayMin;
+            max = displayMax;
+            log = layerLog;
+            have = true;
+            break;
+
+        } else {
+
+            if (!have || layerMin < min) min = layerMin;
+            if (!have || layerMax > max) max = layerMax;
+            if (!have && layerLog) log = true;
+            have = true;
         }
     }
 
     return have;
 }
 
+bool
+View::getVisibleExtentsForAnyUnit(double &min, double &max,
+                                  bool &log, QString &unit) const
+{
+    bool have = false;
+
+    // Iterate in reverse order, so as to return display extents of
+    // topmost layer that fits the bill
+    
+    for (auto i = m_layerStack.rbegin(); i != m_layerStack.rend(); ++i) { 
+
+        Layer *layer = *i;
+
+        if (layer->isLayerDormant(this)) {
+            continue;
+        }
+        
+        QString layerUnit;
+        double layerMin = 0.0, layerMax = 0.0;
+        bool layerLog = false;
+
+        if (!layer->getValueExtents(layerMin, layerMax, layerLog, layerUnit)) {
+            continue;
+        }
+        if (layerUnit == "") {
+            continue;
+        }
+
+        double displayMin = 0.0, displayMax = 0.0;
+        
+        if (layer->getDisplayExtents(displayMin, displayMax)) {
+
+            min = displayMin;
+            max = displayMax;
+            log = layerLog;
+            unit = layerUnit;
+            have = true;
+            break;
+        }
+    }
+
+    return have;
+}
+
 int
-View::getTextLabelHeight(const Layer *layer, QPainter &paint) const
+View::getTextLabelYCoord(const Layer *layer, QPainter &paint) const
 {
     std::map<int, Layer *> sortedLayers;
 
diff -r 5a215033b853 -r 4f8c72adbf43 view/View.h
--- a/view/View.h	Tue Oct 15 09:32:24 2019 +0100
+++ b/view/View.h	Tue Oct 15 11:40:56 2019 +0100
@@ -350,11 +350,25 @@
      */
     virtual bool renderPartToSvgFile(QString filename,
                                      sv_frame_t f0, sv_frame_t f1);
+
+    /**
+     * Return the visible vertical extents for the given unit, if any.
+     * Overridden from LayerGeometryProvider (see docs there).
+     */
+    bool getVisibleExtentsForUnit(QString unit, double &min, double &max,
+                                  bool &log) const override;
+
+    /**
+     * Return some visible vertical extents and unit. That is, if at
+     * least one non-dormant layer has a non-empty unit and returns
+     * some values from its getDisplayExtents() method, return the
+     * extents and unit from the topmost of those. Otherwise return
+     * false.
+     */
+    bool getVisibleExtentsForAnyUnit(double &min, double &max,
+                                     bool &logarithmic, QString &unit) const;
     
-    int getTextLabelHeight(const Layer *layer, QPainter &) const override;
-
-    bool getValueExtents(QString unit, double &min, double &max,
-                         bool &log) const override;
+    int getTextLabelYCoord(const Layer *layer, QPainter &) const override;
 
     void toXml(QTextStream &stream, QString indent = "",
                        QString extraAttributes = "") const override;
diff -r 5a215033b853 -r 4f8c72adbf43 view/ViewProxy.h
--- a/view/ViewProxy.h	Tue Oct 15 09:32:24 2019 +0100
+++ b/view/ViewProxy.h	Tue Oct 15 11:40:56 2019 +0100
@@ -95,27 +95,23 @@
         return m_view->getFrequencyForY
             (y / m_scaleFactor, minFreq, maxFreq, logarithmic);
     }
-    int getTextLabelHeight(const Layer *layer, QPainter &paint) const override {
-        return m_scaleFactor * m_view->getTextLabelHeight(layer, paint);
+    int getTextLabelYCoord(const Layer *layer, QPainter &paint) const override {
+        return m_scaleFactor * m_view->getTextLabelYCoord(layer, paint);
     }
-    bool getValueExtents(QString unit, double &min, double &max,
-                                 bool &log) const override {
-        return m_view->getValueExtents(unit, min, max, log);
+    bool getVisibleExtentsForUnit(QString unit, double &min, double &max,
+                                  bool &log) const override {
+        return m_view->getVisibleExtentsForUnit(unit, min, max, log);
     }
     ZoomLevel getZoomLevel() const override {
         ZoomLevel z = m_view->getZoomLevel();
-        //!!!
-//        cerr << "getZoomLevel: from " << z << " to ";
         if (z.zone == ZoomLevel::FramesPerPixel) {
             z.level /= m_scaleFactor;
             if (z.level < 1) {
                 z.level = 1;
             }
         } else {
-            //!!!???
             z.level *= m_scaleFactor;
         }
-//        cerr << z << endl;
         return z;
     }
     QRect getPaintRect() const override {