diff options
Diffstat (limited to 'src/3rdparty/freetype/include/freetype/ftlcdfil.h')
| -rw-r--r-- | src/3rdparty/freetype/include/freetype/ftlcdfil.h | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/src/3rdparty/freetype/include/freetype/ftlcdfil.h b/src/3rdparty/freetype/include/freetype/ftlcdfil.h index c6995f2ff7..d3723e16f6 100644 --- a/src/3rdparty/freetype/include/freetype/ftlcdfil.h +++ b/src/3rdparty/freetype/include/freetype/ftlcdfil.h @@ -5,7 +5,7 @@ * FreeType API for color filtering of subpixel bitmap glyphs * (specification). * - * Copyright (C) 2006-2020 by + * Copyright (C) 2006-2023 by * David Turner, Robert Wilhelm, and Werner Lemberg. * * This file is part of the FreeType project, and may only be used, @@ -44,7 +44,7 @@ FT_BEGIN_HEADER * API to control subpixel rendering. * * @description: - * FreeType provides two alternative subpixel rendering technologies. + * FreeType provides two alternative subpixel rendering technologies. * Should you define `FT_CONFIG_OPTION_SUBPIXEL_RENDERING` in your * `ftoption.h` file, this enables ClearType-style rendering. * Otherwise, Harmony LCD rendering is enabled. These technologies are @@ -55,13 +55,12 @@ FT_BEGIN_HEADER * ClearType-style LCD rendering exploits the color-striped structure of * LCD pixels, increasing the available resolution in the direction of * the stripe (usually horizontal RGB) by a factor of~3. Using the - * subpixels coverages unfiltered can create severe color fringes + * subpixel coverages unfiltered can create severe color fringes * especially when rendering thin features. Indeed, to produce * black-on-white text, the nearby color subpixels must be dimmed - * equally. - * - * A good 5-tap FIR filter should be applied to subpixel coverages - * regardless of pixel boundaries and should have these properties: + * evenly. Therefore, an equalizing 5-tap FIR filter should be applied + * to subpixel coverages regardless of pixel boundaries and should have + * these properties: * * 1. It should be symmetrical, like {~a, b, c, b, a~}, to avoid * any shifts in appearance. @@ -84,7 +83,7 @@ FT_BEGIN_HEADER * Harmony LCD rendering is suitable to panels with any regular subpixel * structure, not just monitors with 3 color striped subpixels, as long * as the color subpixels have fixed positions relative to the pixel - * center. In this case, each color channel is then rendered separately + * center. In this case, each color channel can be rendered separately * after shifting the outline opposite to the subpixel shift so that the * coverage maps are aligned. This method is immune to color fringes * because the shifts do not change integral coverage. @@ -101,9 +100,9 @@ FT_BEGIN_HEADER * clockwise. Harmony with default LCD geometry is equivalent to * ClearType with light filter. * - * As a result of ClearType filtering or Harmony rendering, the - * dimensions of LCD bitmaps can be either wider or taller than the - * dimensions of the corresponding outline with regard to the pixel grid. + * As a result of ClearType filtering or Harmony shifts, the resulting + * dimensions of LCD bitmaps can be slightly wider or taller than the + * dimensions the original outline with regard to the pixel grid. * For example, for @FT_RENDER_MODE_LCD, the filter adds 2~subpixels to * the left, and 2~subpixels to the right. The bitmap offset values are * adjusted accordingly, so clients shouldn't need to modify their layout @@ -138,11 +137,11 @@ FT_BEGIN_HEADER * * FT_LCD_FILTER_DEFAULT :: * This is a beveled, normalized, and color-balanced five-tap filter - * with weights of [0x08 0x4D 0x56 0x4D 0x08] in 1/256th units. + * with weights of [0x08 0x4D 0x56 0x4D 0x08] in 1/256 units. * * FT_LCD_FILTER_LIGHT :: * this is a boxy, normalized, and color-balanced three-tap filter with - * weights of [0x00 0x55 0x56 0x55 0x00] in 1/256th units. + * weights of [0x00 0x55 0x56 0x55 0x00] in 1/256 units. * * FT_LCD_FILTER_LEGACY :: * FT_LCD_FILTER_LEGACY1 :: @@ -227,7 +226,7 @@ FT_BEGIN_HEADER * * weights :: * A pointer to an array; the function copies the first five bytes and - * uses them to specify the filter weights in 1/256th units. + * uses them to specify the filter weights in 1/256 units. * * @return: * FreeType error code. 0~means success. |