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Fix for Windows and X11: Rounding issues with Fl_RGB_Image::draw() (#1120)

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This commit is contained in:
ManoloFLTK 2024-11-12 10:56:19 +01:00
parent 0d4c8c8534
commit 2337214e4e
2 changed files with 10 additions and 4 deletions
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5
FL/Fl_Graphics_Driver.H
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@ -413,10 +413,7 @@ class FL_EXPORT Fl_Scalable_Graphics_Driver : public Fl_Graphics_Driver {
Fl_Fontsize fontsize_; // scale-independent font size value Fl_Fontsize fontsize_; // scale-independent font size value
public: public:
Fl_Scalable_Graphics_Driver(); Fl_Scalable_Graphics_Driver();
// This function aims to compute accurately int(x * s) in static int floor(int x, float s);
// presence of rounding errors existing with floating point numbers
// and that sometimes differ between 32 and 64 bits.
static inline int floor(int x, float s) { return int(x * s + 0.001f); }
inline int floor(int x) { return Fl_Scalable_Graphics_Driver::floor(x, scale()); } inline int floor(int x) { return Fl_Scalable_Graphics_Driver::floor(x, scale()); }
protected: protected:
int line_width_; int line_width_;

9
src/Fl_Graphics_Driver.cxx
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@ -759,6 +759,15 @@ void Fl_Scalable_Graphics_Driver::rect(int x, int y, int w, int h)
} }
} }
// This function aims to compute accurately int(x * s) in
// presence of rounding errors existing with floating point numbers
// and that sometimes differ between 32 and 64 bits.
int Fl_Scalable_Graphics_Driver::floor(int x, float s) {
if (s == 1) return x;
int retval = int(abs(x) * s + 0.001f);
return (x >= 0 ? retval : -retval);
}
void Fl_Scalable_Graphics_Driver::rectf(int x, int y, int w, int h) void Fl_Scalable_Graphics_Driver::rectf(int x, int y, int w, int h)
{ {
if (w <= 0 || h <= 0) return; if (w <= 0 || h <= 0) return;