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libbreezecommon/breezeboxshadowrenderer.cpp
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| 40 | { | 40 | { | ||
| 41 | // See https://www.w3.org/TR/SVG11/filters.html#feGaussianBlurElement | 41 | // See https://www.w3.org/TR/SVG11/filters.html#feGaussianBlurElement | ||
| 42 | const qreal gaussianScaleFactor = (3.0 * qSqrt(2.0 * M_PI) / 4.0) * 1.5; | 42 | const qreal gaussianScaleFactor = (3.0 * qSqrt(2.0 * M_PI) / 4.0) * 1.5; | ||
| 43 | return qMax(2, qFloor(stdDev * gaussianScaleFactor + 0.5)); | 43 | return qMax(2, qFloor(stdDev * gaussianScaleFactor + 0.5)); | ||
| 44 | } | 44 | } | ||
| 45 | 45 | | |||
| 46 | static inline qreal calculateBlurStdDev(int radius) | 46 | static inline qreal calculateBlurStdDev(int radius) | ||
| 47 | { | 47 | { | ||
| 48 | // https://www.w3.org/TR/css-backgrounds-3/#shadow-blur says that the resulting | 48 | return radius * 0.5; | ||
| 49 | // shadow must approximate the image that would be generated by applying to the | | |||
| 50 | // shadow a Gaussian blur with a standard deviation equal to half the blur radius, | | |||
| 51 | // but we had been using a slightly different (non-standard compliant) routine to | | |||
| 52 | // derive the standard deviation before, so in order to not break existing shadow | | |||
| 53 | // params, we're not following the standard. | | |||
| 54 | return radius * 0.43; // TODO: Multiply by 0.5 instead. | | |||
| 55 | } | 49 | } | ||
| 56 | 50 | | |||
| 57 | static inline QSize calculateBlurExtent(int radius) | 51 | static inline QSize calculateBlurExtent(int radius) | ||
| 58 | { | 52 | { | ||
| 59 | const int blurRadius = calculateBlurRadius(calculateBlurStdDev(radius)); | 53 | const int blurRadius = calculateBlurRadius(calculateBlurStdDev(radius)); | ||
| 60 | return QSize(blurRadius, blurRadius); | 54 | return QSize(blurRadius, blurRadius); | ||
| 61 | } | 55 | } | ||
| 62 | 56 | | |||
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