Add a new Dial widget based on the knob of the Slider widget

CMakeLists.txt

@@ -330,6 +330,7 @@ add_library(nanogui-obj OBJECT
   include/nanogui/combobox.h src/combobox.cpp
   include/nanogui/progressbar.h src/progressbar.cpp
   include/nanogui/slider.h src/slider.cpp
+  include/nanogui/dial.h src/dial.cpp
   include/nanogui/messagedialog.h src/messagedialog.cpp
   include/nanogui/textbox.h src/textbox.cpp
   include/nanogui/imagepanel.h src/imagepanel.cpp

include/nanogui/dial.h

@@ -0,0 +1,56 @@
+/*
+    nanogui/dial.h -- Fractional dial widget with mouse control
+
+    NanoGUI was developed by Wenzel Jakob <[email protected]>.
+    The widget drawing code is based on the NanoVG demo application
+    by Mikko Mononen.
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE.txt file.
+*/
+/** \file */
+
+#pragma once
+
+#include <nanogui/widget.h>
+
+NAMESPACE_BEGIN(nanogui)
+
+/**
+ * \class Dial dial.h nanogui/dial.h
+ *
+ * \brief Fractional dial widget with mouse control.
+ */
+class NANOGUI_EXPORT Dial : public Widget {
+public:
+    Dial(Widget *parent);
+
+    float value() const { return mValue; }
+    void setValue(float value) { mValue = value; }
+
+    std::pair<float, float> range() const { return mRange; }
+    void setRange(std::pair<float, float> range) { mRange = range; }
+
+    std::function<void(float)> callback() const { return mCallback; }
+    void setCallback(const std::function<void(float)> &callback) { mCallback = callback; }
+
+    std::function<void(float)> finalCallback() const { return mFinalCallback; }
+    void setFinalCallback(const std::function<void(float)> &callback) { mFinalCallback = callback; }
+
+    virtual Vector2i preferredSize(NVGcontext *ctx) const override;
+    virtual bool mouseDragEvent(const Vector2i &p, const Vector2i &rel, int button, int modifiers) override;
+    virtual bool mouseButtonEvent(const Vector2i &p, int button, bool down, int modifiers) override;
+    virtual void draw(NVGcontext* ctx) override;
+    virtual void save(Serializer &s) const override;
+    virtual bool load(Serializer &s) override;
+
+protected:
+    float mValue;
+    std::function<void(float)> mCallback;
+    std::function<void(float)> mFinalCallback;
+    std::pair<float, float> mRange;
+public:
+    EIGEN_MAKE_ALIGNED_OPERATOR_NEW
+};
+
+NAMESPACE_END(nanogui)

include/nanogui/nanogui.h

@@ -29,6 +29,7 @@
 #include <nanogui/messagedialog.h>
 #include <nanogui/textbox.h>
 #include <nanogui/slider.h>
+#include <nanogui/dial.h>
 #include <nanogui/imagepanel.h>
 #include <nanogui/imageview.h>
 #include <nanogui/vscrollpanel.h>

src/dial.cpp

@@ -0,0 +1,130 @@
+/*
+    nanogui/dial.cpp -- Fractional dial widget with mouse control
+
+    NanoGUI was developed by Wenzel Jakob <[email protected]>.
+    The widget drawing code is based on the NanoVG demo application
+    by Mikko Mononen.
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE.txt file.
+*/
+
+#include <nanogui/dial.h>
+#include <nanogui/theme.h>
+#include <nanogui/opengl.h>
+#include <nanogui/serializer/core.h>
+#include <Eigen/Geometry>
+
+using Eigen::Rotation2Df;
+
+NAMESPACE_BEGIN(nanogui)
+
+Dial::Dial(Widget *parent)
+    : Widget(parent), mValue(0.0f), mRange(0.f, 1.f) {
+}
+
+Vector2i Dial::preferredSize(NVGcontext *) const {
+    return Vector2i(40, 40);
+}
+
+bool Dial::mouseDragEvent(const Vector2i &p, const Vector2i & /* rel */,
+                            int /* button */, int /* modifiers */) {
+    if (!mEnabled)
+        return false;
+
+    Vector2f pos = (p - mPos - mSize/2).cast<float>();
+    float value = 0.5f + 0.5f*atan2f(pos.x(), -pos.y())/NVG_PI;
+    value = -0.1f + 1.2f*value;
+
+    value = value * (mRange.second - mRange.first) + mRange.first;
+    mValue = std::min(std::max(value, mRange.first), mRange.second);
+    if (mCallback)
+        mCallback(mValue);
+
+    return true;
+}
+
+bool Dial::mouseButtonEvent(const Vector2i &p, int /* button */, bool down, int /* modifiers */) {
+    if (!mEnabled)
+        return false;
+
+    if (down) {
+        Vector2f pos = (p - mPos - mSize/2).cast<float>();
+        float kr = 0.5f * (mSize.y() * 0.4f);
+
+        if (pos.squaredNorm() >= kr*kr) {
+            float value = 0.5f + 0.5f*atan2f(pos.x(), -pos.y())/NVG_PI;
+            value = -0.1f + 1.2f*value;
+
+            value = value * (mRange.second - mRange.first) + mRange.first;
+            mValue = std::min(std::max(value, mRange.first), mRange.second);
+        }
+        if (mCallback)
+            mCallback(mValue);
+    } else if (mFinalCallback) {
+        mFinalCallback(mValue);
+    }
+
+    return true;
+}
+
+void Dial::draw(NVGcontext* ctx) {
+    Vector2f center = mPos.cast<float>() + mSize.cast<float>() * 0.5f;
+    float kr = (int) (mSize.y() * 0.4f), kshadow = 2;
+
+    Vector2f dialPos(center.x(), center.y() + 0.5f);
+
+    NVGpaint dial = nvgLinearGradient(ctx,
+        mPos.x(), center.y() - kr, mPos.x(), center.y() + kr,
+        mTheme->mBorderLight, mTheme->mBorderMedium);
+    NVGpaint dialReverse = nvgLinearGradient(ctx,
+        mPos.x(), center.y() - kr, mPos.x(), center.y() + kr,
+        mTheme->mBorderMedium,
+        mTheme->mBorderLight);
+
+    NVGpaint dialFace = nvgRadialGradient(ctx,
+        dialPos.x(), dialPos.y(), kr - kshadow,
+        kr + kshadow, Color(150, mEnabled ? 255 : 100), mTheme->mTransparent);
+
+    nvgBeginPath(ctx);
+    nvgCircle(ctx, dialPos.x(), dialPos.y(), kr);
+    nvgStrokeColor(ctx, mTheme->mBorderDark);
+    nvgFillPaint(ctx, dial);
+    nvgStroke(ctx);
+    nvgFill(ctx);
+    nvgBeginPath(ctx);
+    nvgCircle(ctx, dialPos.x(), dialPos.y(), kr - kshadow);
+    nvgFillPaint(ctx, dialFace);
+    nvgStrokePaint(ctx, dialReverse);
+    nvgStroke(ctx);
+    nvgFill(ctx);
+
+    Vector2f notchPos(0.0f, 0.8f*(kr - 1.5f*kshadow));
+    float value = (mValue - mRange.first)/(mRange.second - mRange.first);
+    float theta = 2.0f*NVG_PI*(0.1f + 0.8f*value);
+    Rotation2Df t(theta);
+    notchPos = t*notchPos;
+    notchPos += dialPos;
+
+    nvgBeginPath(ctx);
+    nvgCircle(ctx, notchPos.x(), notchPos.y(), 0.15f*kr);
+    nvgFillColor(ctx, Color(mEnabled ? 50 : 100, 150));
+    nvgStrokePaint(ctx, dial);
+    nvgStroke(ctx);
+    nvgFill(ctx);
+}
+
+void Dial::save(Serializer &s) const {
+    Widget::save(s);
+    s.set("value", mValue);
+    s.set("range", mRange);
+}
+
+bool Dial::load(Serializer &s) {
+    if (!Widget::load(s)) return false;
+    if (!s.get("value", mValue)) return false;
+    if (!s.get("range", mRange)) return false;
+    return true;
+}
+
+NAMESPACE_END(nanogui)

src/example1.cpp

@@ -18,6 +18,7 @@
 #include <nanogui/layout.h>
 #include <nanogui/label.h>
 #include <nanogui/checkbox.h>
+#include <nanogui/dial.h>
 #include <nanogui/button.h>
 #include <nanogui/toolbutton.h>
 #include <nanogui/popupbutton.h>
@@ -35,6 +36,7 @@
 #include <nanogui/graph.h>
 #include <nanogui/tabwidget.h>
 #include <iostream>
+#include <sstream>
 #include <string>
 
 // Includes for the GLTexture class.
@@ -334,6 +336,33 @@ class ExampleApplication : public nanogui::Screen {
         textBox->setFontSize(20);
         textBox->setAlignment(TextBox::Alignment::Right);
 
+        new Label(window, "Dial and text box", "sans-bold");
+
+        panel = new Widget(window);
+        panel->setLayout(new BoxLayout(Orientation::Horizontal,
+                                       Alignment::Middle, 0, 20));
+
+        Dial *dial = new Dial(panel);
+        dial->setValue(0.01f);
+        dial->setFixedWidth(80);
+
+        textBox = new TextBox(panel);
+        textBox->setFixedSize(Vector2i(60, 25));
+        textBox->setValue("0.01");
+        dial->setCallback([textBox](float value) {
+            value = 0.01f + 99.99f*powf(value, 5.0f);
+            std::ostringstream sval;
+            sval.precision(2); sval << std::fixed << value;
+            textBox->setValue(sval.str());
+        });
+        dial->setFinalCallback([&](float value) {
+            value = 0.01f + 99.99f*powf(value, 5.0f);
+            cout << "Final dial value: " << value << endl;
+        });
+        textBox->setFixedSize(Vector2i(60,25));
+        textBox->setFontSize(20);
+        textBox->setAlignment(TextBox::Alignment::Right);
+
         window = new Window(this, "Misc. widgets");
         window->setPosition(Vector2i(425,15));
         window->setLayout(new GroupLayout());