File indexing completed on 2024-05-12 04:44:33

 // SPDX-FileCopyrightText: Lukas Sommer <sommerluk@gmail.com>
 // SPDX-License-Identifier: BSD-2-Clause OR MIT
 
 #ifndef HELPERCONSTANTS_H
 #define HELPERCONSTANTS_H
 
 #include <qglobal.h>
 #include <qstring.h>
 
 /** @internal
  *
  * @file
  *
  * Provides global constant values. */
 
 namespace PerceptualColor
 {
 
 /** @internal
  *
  * @brief Precision for gamut boundary search
  *
  * We have to search sometimes for the gamut boundary. This value defines
  * the precision of the search:  Smaller values mean better precision and
  * slower processing. */
 constexpr qreal gamutPrecisionCielab = 0.001;
 
 /** @internal
  *
  * @brief Precision for gamut boundary search
  *
  * We have to search sometimes for the gamut boundary. This value defines
  * the precision of the search:  Smaller values mean better precision and
  * slower processing. */
 constexpr qreal gamutPrecisionOklab = gamutPrecisionCielab / 100;
 
 /** @internal
  *
  * @brief The overlap is a recommended tolerance value, measured in physical
  * pixels.
  *
  * It can be used during the painting process to paint “a little bit more
  * surface than requested”, just to be sure no pixel is missing. We
  * choose <tt>2</tt> because this value might also be used for radius
  * values, and at 45°, going from one edge of a pixel to the opposite edge
  * yet has a distance of √2 ≈ 1,41, which we round up to <tt>2</tt> just
  * to be sure. */
 constexpr int overlap = 2;
 
 /** @internal
  *
  * @brief Proposed scale factor for gradients
  *
  * Widgets provide a <tt>minimumSizeHint</tt> and a <tt>sizeHint</tt>.
  * This value provides a scale factor that is multiplied with
  * <tt>minimumSizeHint</tt> to get an appropriate <tt>sizeHint</tt>.
  * This scale factor is meant for gradient-based widgets. */
 // This value is somewhat arbitrary…
 constexpr qreal scaleFromMinumumSizeHintToSizeHint = 1.2;
 
 /** @internal
  *
  * @brief Amount of single step for alpha.
  *
  * Measured for an alpha range from 0 (transparent) to 1 (opaque).
  *
  * The smaller of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * @sa @ref pageStepAlpha */
 constexpr qreal singleStepAlpha = 0.01;
 
 /** @internal
  *
  * @brief Amount of single step for chroma.
  *
  * Measured in LCH chroma units.
  *
  * The smaller of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * @sa @ref pageStepChroma */
 constexpr int singleStepChroma = 1;
 
 /** @internal
  *
  * @brief Amount of single step for hue.
  *
  * Measured in degree.
  *
  * The smaller of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * @sa @ref pageStepHue
  *
  * @todo What would be a good value for this? Its effect depends on
  * chroma: On higher chroma, the same step in hue means a bigger visual
  * color difference. We could even calculate that, but it does not seem to
  * be very intuitive if the reaction on mouse wheel events are different
  * depending on chroma - that would not be easy to understand for the
  * user. And it might be better that the user this way also notices
  * intuitively that hue changes are not linear across chroma. Anyway:
  * What would be a sensible default step? */
 constexpr int singleStepHue = 360 / 100;
 
 /** @internal
  *
  * @brief Amount of single step for lightness.
  *
  * Measured in LCH lightness units.
  *
  * The smaller of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * @sa @ref pageStepLightness */
 constexpr int singleStepLightness = 1;
 
 /** @internal
  *
  * @brief Amount of single step for Ok lightness, a, b, chroma (but
  * <em>not</em> hue).
  *
  * Measured in Ok units.
  *
  * The smaller of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value. */
 constexpr double singleStepOklabc = 0.01;
 
 /** @internal
  *
  * @brief Amount of page step for alpha.
  *
  * Measured for an alpha range from 0 (transparent) to 1 (opaque).
  *
  * The larger of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * The value is 10 times @ref singleStepChroma. This behavior
  * corresponds to QAbstractSlider, who’s page step is also 10 times bigger than
  * its single step. */
 constexpr qreal pageStepAlpha = 10 * singleStepAlpha;
 
 /** @internal
  *
  * @brief Amount of page step for chroma.
  *
  * Measured in LCH chroma units.
  *
  * The larger of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * The value is 10 times @ref singleStepChroma. This behavior
  * corresponds to QAbstractSlider, who’s page step is also 10 times bigger than
  * its single step. */
 constexpr int pageStepChroma = 10 * singleStepChroma;
 
 /** @internal
  *
  * @brief Amount of page step for hue.
  *
  * Measured in degree.
  *
  * The larger of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * The value is 10 times @ref singleStepHue. This behavior
  * corresponds to QAbstractSlider, who’s page step is also 10 times bigger than
  * its single step. */
 constexpr int pageStepHue = 10 * singleStepHue;
 
 /** @internal
  *
  * @brief Amount of page step for lightness.
  *
  * Measured in LCH lightness units.
  *
  * The larger of two natural steps that a widget provides and
  * typically corresponds to the user pressing a key or using the mouse
  * wheel: The value will be incremented/decremented by the amount of this
  * value.
  *
  * The value is 10 times @ref singleStepLightness. This behavior
  * corresponds to QAbstractSlider, who’s page step is also 10 times bigger than
  * its single step. */
 constexpr int pageStepLightness = 10 * singleStepLightness;
 
 /** @internal
  *
  * @brief Invisible marker for rich text
  *
  * Some parts of Qt accept both, plain text and rich text, within the same
  * property. Example: <tt>QToolTip</tt> uses <tt>Qt::mightBeRichText()</tt>
  * to decide if a text is treated as rich text or as plain text. But
  * <tt>Qt::mightBeRichText()</tt> is only a raw guess. This situation
  * is not comfortable: You never really know in advance if text will be
  * treated as rich text or as plain text.
  *
  * This function provides a solution. It provides a rich text marker. If
  * your text starts with this marker, it will always be treated
  * as rich text. The marker itself will not be visible in the rendered
  * rich text.
  *
  * Usage example:
  * @snippet testhelperconstants.cpp richTextMarkerExample */
 inline const QString richTextMarker = QStringLiteral(u"<a/>");
 
 } // namespace PerceptualColor
 
 #endif // HELPERCONSTANTS_H