Add option to switch dynamic gradient between BG>FG and FG>BG

data/widgets/dynamics.xml

@@ -41,7 +41,7 @@
 
       <label id="gradient_label" text="@.gradient" style="mini_label"  />
       <hbox id="gradient_placeholder" cell_vspan="2" />
-      <boxfiller />
+      <link id="gradient_from_to" style="mini_label"  />
 
       <separator id="separator2" text="@.sensors_tweaks" horizontal="true" cell_hspan="2" />
 

src/app/tools/dynamics.h

@@ -19,6 +19,11 @@ namespace tools {
     Velocity,
   };
 
+  enum class ColorFromTo {
+    BgToFg,
+    FgToBg,
+  };
+
   struct DynamicsOptions {
     DynamicSensor size = DynamicSensor::Static;
     DynamicSensor angle = DynamicSensor::Static;
@@ -26,6 +31,7 @@ namespace tools {
     int minSize = 0;
     int minAngle = 0;
     render::DitheringMatrix ditheringMatrix;
+    ColorFromTo colorFromTo = ColorFromTo::BgToFg;
     float minPressureThreshold = 0.0f, maxPressureThreshold = 1.0f;
     float minVelocityThreshold = 0.0f, maxVelocityThreshold = 1.0f;
 

src/app/tools/point_shapes.h

@@ -65,8 +65,15 @@ public:
 
     // For dynamic gradient
     m_hasDynamicGradient = (m_dynamics.gradient != DynamicSensor::Static);
-    m_primaryColor = loop->getPrimaryColor();
-    m_secondaryColor = loop->getSecondaryColor();
+    if (m_hasDynamicGradient &&
+        m_dynamics.colorFromTo == ColorFromTo::FgToBg) {
+      m_primaryColor = loop->getSecondaryColor();
+      m_secondaryColor = loop->getPrimaryColor();
+    }
+    else {
+      m_primaryColor = loop->getPrimaryColor();
+      m_secondaryColor = loop->getSecondaryColor();
+    }
     m_lastGradientValue = -1;
   }
 

src/app/ui/dynamics_popup.cpp

@@ -213,6 +213,7 @@ DynamicsPopup::DynamicsPopup(Delegate* delegate)
   , m_delegate(delegate)
   , m_dynamics(new gen::Dynamics)
   , m_ditheringSel(new DitheringSelector(DitheringSelector::SelectMatrix))
+  , m_fromTo(tools::ColorFromTo::BgToFg)
 {
   m_dynamics->values()->ItemChange.connect(
     [this](ButtonSet::Item* item){
@@ -226,6 +227,14 @@ DynamicsPopup::DynamicsPopup(Delegate* delegate)
     [this]{
       m_delegate->setMaxAngle(m_dynamics->maxAngle()->getValue());
     });
+  m_dynamics->gradientFromTo()->Click.connect(
+    [this]{
+      if (m_fromTo == tools::ColorFromTo::BgToFg)
+        m_fromTo = tools::ColorFromTo::FgToBg;
+      else
+        m_fromTo = tools::ColorFromTo::BgToFg;
+      updateFromToText();
+    });
 
   m_dynamics->gradientPlaceholder()->addChild(m_ditheringSel);
   m_dynamics->pressurePlaceholder()->addChild(m_pressureThreshold = new ThresholdSlider);
@@ -253,6 +262,7 @@ tools::DynamicsOptions DynamicsPopup::getDynamics() const
   opts.minSize = m_dynamics->minSize()->getValue();
   opts.minAngle = m_dynamics->minAngle()->getValue();
   opts.ditheringMatrix = m_ditheringSel->ditheringMatrix();
+  opts.colorFromTo = m_fromTo;
 
   opts.minPressureThreshold = m_pressureThreshold->minThreshold();
   opts.maxPressureThreshold = m_pressureThreshold->maxThreshold();
@@ -349,6 +359,8 @@ void DynamicsPopup::onValuesChange(ButtonSet::Item* item)
 
   m_dynamics->gradientLabel()->setVisible(needsGradient);
   m_dynamics->gradientPlaceholder()->setVisible(needsGradient);
+  m_dynamics->gradientFromTo()->setVisible(needsGradient);
+  updateFromToText();
 
   m_dynamics->separator()->setVisible(any);
   m_dynamics->options()->setVisible(any);
@@ -369,6 +381,13 @@ void DynamicsPopup::onValuesChange(ButtonSet::Item* item)
     manager()->invalidateRect(oldBounds);
 }
 
+void DynamicsPopup::updateFromToText()
+{
+  m_dynamics->gradientFromTo()->setText(
+    m_fromTo == tools::ColorFromTo::BgToFg ? "BG > FG":
+    m_fromTo == tools::ColorFromTo::FgToBg ? "FG > BG": "-");
+}
+
 bool DynamicsPopup::onProcessMessage(Message* msg)
 {
   switch (msg->type()) {

src/app/ui/dynamics_popup.h

@@ -43,6 +43,7 @@ namespace app {
     bool isCheck(int i) const;
     void onValuesChange(ButtonSet::Item* item);
     bool onProcessMessage(ui::Message* msg) override;
+    void updateFromToText();
 
     Delegate* m_delegate;
     gen::Dynamics* m_dynamics;
@@ -51,6 +52,7 @@ namespace app {
     ThresholdSlider* m_pressureThreshold;
     ThresholdSlider* m_velocityThreshold;
     tools::VelocitySensor m_velocity;
+    tools::ColorFromTo m_fromTo;
   };
 
 } // namespace app