Rework some color code

dgl/Color.hpp

@@ -48,13 +48,13 @@ struct Color {
       Create a color from red, green, blue and alpha numeric values.
       Values must be in [0..255] range.
     */
-    Color(const int red, const int green, const int blue, const int alpha = 255) noexcept;
+    Color(int red, int green, int blue, int alpha = 255) noexcept;
 
    /**
       Create a color from red, green, blue and alpha floating-point values.
       Values must in [0..1] range.
     */
-    Color(const float red, const float green, const float blue, const float alpha = 1.0f) noexcept;
+    Color(float red, float green, float blue, float alpha = 1.0f) noexcept;
 
    /**
       Create a color by copying another color.
@@ -65,25 +65,33 @@ struct Color {
    /**
       Create a color by linearly interpolating two other colors.
     */
-    Color(const Color& color1, const Color& color2, const float u) noexcept;
+    Color(const Color& color1, const Color& color2, float u) noexcept;
 
    /**
-      Create a color specified by hue, saturation, lightness and alpha.
-      HSL values are all in [0..1] range, alpha in [0..255] range.
+      Create a color specified by hue, saturation and lightness.
+      Values must in [0..1] range.
     */
-    static Color HSL(const float hue, const float saturation, const float lightness, const int alpha = 255);
+    static Color fromHSL(float hue, float saturation, float lightness, float alpha = 1.0f);
 
    /**
       Linearly interpolate this color against another.
     */
-    void interpolate(const Color& other, const float u) noexcept;
+    void interpolate(const Color& other, float u) noexcept;
 
    /**
       Check if this color matches another.
+      @note: Comparison is forced within 8-bit color values.
     */
+    bool isEqual(const Color& color, bool withAlpha = true) noexcept;
+    bool isNotEqual(const Color& color, bool withAlpha = true) noexcept;
     bool operator==(const Color& color) noexcept;
     bool operator!=(const Color& color) noexcept;
 
+   /**
+      Fix color bounds if needed.
+    */
+    void fixBounds() noexcept;
+
    /**
       @internal
       Needed for NanoVG compatibility.

dgl/src/Color.cpp

@@ -22,51 +22,66 @@ START_NAMESPACE_DGL
 
 // -----------------------------------------------------------------------
 
-Color::Color() noexcept
-    : red(1.0f), green(1.0f), blue(1.0f), alpha(1.0f) {}
-
-Color::Color(const int r, const int g, const int b, const int a) noexcept
-    : red(static_cast<float>(r)/255.0f), green(static_cast<float>(g)/255.0f), blue(static_cast<float>(b)/255.0f), alpha(static_cast<float>(a)/255.0f) {}
-
-Color::Color(const float r, const float g, const float b, const float a) noexcept
-    : red(r), green(g), blue(b), alpha(a) {}
-
-Color::Color(const Color& color) noexcept
-    : red(color.red), green(color.green), blue(color.blue), alpha(color.alpha) {}
-
-Color::Color(const Color& color1, const Color& color2, const float u) noexcept
-    : red(color1.red), green(color1.green), blue(color1.blue), alpha(color1.alpha)
+static void fixRange(float& value)
 {
-    interpolate(color2, u);
+    /**/ if (value < 0.0f)
+        value = 0.0f;
+    else if (value > 1.0f)
+        value = 1.0f;
 }
 
-void Color::interpolate(const Color& other, const float u) noexcept
+static float getFixedRange(const float& value)
 {
-    const float u2 = (u < 0.0f) ? 0.0f : ((u > 1.0f) ? 1.0f : u);
-    const float oneMinusU = 1.0f - u;
+    if (value <= 0.0f)
+        return 0.0f;
+    if (value >= 1.0f)
+        return 1.0f;
+    return value;
+}
 
-    red   = red   * oneMinusU + other.red   * u2;
-    green = green * oneMinusU + other.green * u2;
-    blue  = blue  * oneMinusU + other.blue  * u2;
-    alpha = alpha * oneMinusU + other.alpha * u2;
+static uchar getFixedRange2(const float& value)
+{
+    const float value2(getFixedRange(value)*255.0f);
+    if (value2 <= 0.0f)
+        return 0;
+    if (value2 >= 255.0f)
+        return 255;
+    return static_cast<uchar>(value2);
 }
 
-Color Color::HSL(const float hue, const float saturation, const float lightness, const int alpha)
+// -----------------------------------------------------------------------
+
+Color::Color() noexcept
+    : red(1.0f),
+      green(1.0f),
+      blue(1.0f),
+      alpha(1.0f) {}
+
+Color::Color(int r, int g, int b, int a) noexcept
+    : red(static_cast<float>(r)/255.0f),
+      green(static_cast<float>(g)/255.0f),
+      blue(static_cast<float>(b)/255.0f),
+      alpha(static_cast<float>(a)/255.0f)
 {
-    return nvgHSLA(hue, saturation, lightness, alpha);
+    fixBounds();
 }
 
-Color::Color(const NVGcolor& c) noexcept
-    : red(c.r), green(c.g), blue(c.b), alpha(c.a) {}
+Color::Color(float r, float g, float b, float a) noexcept
+    : red(r),
+      green(g),
+      blue(b),
+      alpha(a)
+{
+    fixBounds();
+}
 
-Color::operator NVGcolor() const noexcept
+Color::Color(const Color& color) noexcept
+    : red(color.red),
+      green(color.green),
+      blue(color.blue),
+      alpha(color.alpha)
 {
-    NVGcolor nc;
-    nc.r = red;
-    nc.g = green;
-    nc.b = blue;
-    nc.a = alpha;
-    return nc;
+    fixBounds();
 }
 
 Color& Color::operator=(const Color& color) noexcept
@@ -75,17 +90,111 @@ Color& Color::operator=(const Color& color) noexcept
     green = color.green;
     blue  = color.blue;
     alpha = color.alpha;
+    fixBounds();
     return *this;
 }
 
+Color::Color(const Color& color1, const Color& color2, float u) noexcept
+    : red(color1.red),
+      green(color1.green),
+      blue(color1.blue),
+      alpha(color1.alpha)
+{
+    interpolate(color2, u);
+}
+
+Color Color::fromHSL(float hue, float saturation, float lightness, float alpha)
+{
+    return nvgHSLA(hue, saturation, lightness, static_cast<uchar>(getFixedRange(alpha)*255.0f));
+}
+
+void Color::interpolate(const Color& other, float u) noexcept
+{
+    fixRange(u);
+    const float oneMinusU(1.0f - u);
+
+    red   = red   * oneMinusU + other.red   * u;
+    green = green * oneMinusU + other.green * u;
+    blue  = blue  * oneMinusU + other.blue  * u;
+    alpha = alpha * oneMinusU + other.alpha * u;
+
+    fixBounds();
+}
+
+// -----------------------------------------------------------------------
+
+bool Color::isEqual(const Color& color, bool withAlpha) noexcept
+{
+    const uchar r1 = getFixedRange2(rgba[0]);
+    const uchar g1 = getFixedRange2(rgba[1]);
+    const uchar b1 = getFixedRange2(rgba[2]);
+    const uchar a1 = getFixedRange2(rgba[3]);
+
+    const uchar r2 = getFixedRange2(color.rgba[0]);
+    const uchar g2 = getFixedRange2(color.rgba[1]);
+    const uchar b2 = getFixedRange2(color.rgba[2]);
+    const uchar a2 = getFixedRange2(color.rgba[3]);
+
+    if (withAlpha)
+        return (r1 == r2 && g1 == g2 && b1 == b2 && a1 == a2);
+    else
+        return (r1 == r2 && g1 == g2 && b1 == b2);
+}
+
+bool Color::isNotEqual(const Color& color, bool withAlpha) noexcept
+{
+    const uchar r1 = getFixedRange2(rgba[0]);
+    const uchar g1 = getFixedRange2(rgba[1]);
+    const uchar b1 = getFixedRange2(rgba[2]);
+    const uchar a1 = getFixedRange2(rgba[3]);
+
+    const uchar r2 = getFixedRange2(color.rgba[0]);
+    const uchar g2 = getFixedRange2(color.rgba[1]);
+    const uchar b2 = getFixedRange2(color.rgba[2]);
+    const uchar a2 = getFixedRange2(color.rgba[3]);
+
+    if (withAlpha)
+        return (r1 != r2 || g1 != g2 || b1 != b2 || a1 != a2);
+    else
+        return (r1 != r2 || g1 != g2 || b1 != b2);
+}
+
 bool Color::operator==(const Color& color) noexcept
 {
-    return (red == color.red && green == color.green && blue == color.blue && alpha == color.alpha);
+    return isEqual(color, true);
 }
 
 bool Color::operator!=(const Color& color) noexcept
 {
-    return (red != color.red || green != color.green || blue != color.blue || alpha != color.alpha);
+    return isNotEqual(color, true);
+}
+
+// -----------------------------------------------------------------------
+
+void Color::fixBounds() noexcept
+{
+    fixRange(red);
+    fixRange(green);
+    fixRange(blue);
+    fixRange(alpha);
+}
+
+// -----------------------------------------------------------------------
+
+Color::Color(const NVGcolor& c) noexcept
+    : red(c.r), green(c.g), blue(c.b), alpha(c.a)
+{
+    fixBounds();
+}
+
+Color::operator NVGcolor() const noexcept
+{
+    NVGcolor nc;
+    nc.r = red;
+    nc.g = green;
+    nc.b = blue;
+    nc.a = alpha;
+    return nc;
 }
 
 // -----------------------------------------------------------------------