diff options
-rw-r--r-- | src/gfx.cpp | 14 | ||||
-rw-r--r-- | src/gfx_func.h | 2 | ||||
-rw-r--r-- | src/station_gui.cpp | 6 |
3 files changed, 20 insertions, 2 deletions
diff --git a/src/gfx.cpp b/src/gfx.cpp index 93335de8a..eb62e56fb 100644 --- a/src/gfx.cpp +++ b/src/gfx.cpp @@ -1546,6 +1546,20 @@ void DoPaletteAnimations() } } +/** + * Determine a contrasty text colour for a coloured background. + * @param background Background colour. + * @return TC_BLACK or TC_WHITE depending on what gives a better contrast. + */ +TextColour GetContrastColour(uint8 background) +{ + Colour c = _cur_palette.palette[background]; + /* Compute brightness according to http://www.w3.org/TR/AERT#color-contrast. + * The following formula computes 1000 * brightness^2, with brightness being in range 0 to 255. */ + uint sq1000_brightness = c.r * c.r * 299 + c.g * c.g * 587 + c.b * c.b * 114; + /* Compare with threshold brightness 128 (50%) */ + return sq1000_brightness < 128 * 128 * 1000 ? TC_WHITE : TC_BLACK; +} /** * Initialize _stringwidth_table cache diff --git a/src/gfx_func.h b/src/gfx_func.h index 49d2d35a3..2425a4059 100644 --- a/src/gfx_func.h +++ b/src/gfx_func.h @@ -177,6 +177,8 @@ static inline byte GetCharacterHeight(FontSize size) extern DrawPixelInfo *_cur_dpi; +TextColour GetContrastColour(uint8 background); + /** * All 16 colour gradients * 8 colours per gradient from darkest (0) to lightest (7) diff --git a/src/station_gui.cpp b/src/station_gui.cpp index 4a1fd10aa..32aadbae7 100644 --- a/src/station_gui.cpp +++ b/src/station_gui.cpp @@ -109,6 +109,7 @@ static void StationsWndShowStationRating(int left, int right, int y, CargoID typ if (!cs->IsValid()) return; int colour = cs->rating_colour; + TextColour tc = GetContrastColour(colour); uint w = (minu(amount, units_full) + 5) / 36; int height = GetCharacterHeight(FS_SMALL); @@ -126,7 +127,7 @@ static void StationsWndShowStationRating(int left, int right, int y, CargoID typ } } - DrawString(left + 1, right, y, cs->abbrev, TC_BLACK); + DrawString(left + 1, right, y, cs->abbrev, tc); /* Draw green/red ratings bar (fits into 14 pixels) */ y += height + 2; @@ -455,7 +456,8 @@ public: const CargoSpec *cs = _sorted_cargo_specs[widget - WID_STL_CARGOSTART]; int cg_ofst = HasBit(this->cargo_filter, cs->Index()) ? 2 : 1; GfxFillRect(r.left + cg_ofst, r.top + cg_ofst, r.right - 2 + cg_ofst, r.bottom - 2 + cg_ofst, cs->rating_colour); - DrawString(r.left + cg_ofst, r.right + cg_ofst, r.top + cg_ofst, cs->abbrev, TC_BLACK, SA_HOR_CENTER); + TextColour tc = GetContrastColour(cs->rating_colour); + DrawString(r.left + cg_ofst, r.right + cg_ofst, r.top + cg_ofst, cs->abbrev, tc, SA_HOR_CENTER); } break; } |