the metrics are not. linearHoriAdvance The advance width of the unhinted glyph. Its value is expressed in 16.16 fractional pixels， since the delta values are zero then. FT_Glyph_Metrics Defined in FT_FREETYPE_H (freetype/freetype.h). typedef struct FT_Glyph_Metrics_ {width;height;horiBearingX;horiBearingY;horiAdvance;vertBearingX;vertBearingY;vertAdvance; } FT_Glyph_Metrics ; A structure to model the metrics of a single glyph. The values are expressed in 26.6 fractional pixel format; if the flag has been used while loading the glyph， using the font's units_per_EM value as the ppem. num_subglyphs The number of subglyphs in a composite glyph. This field is only valid for the composite glyph format that should normally only be loaded with the flag. subglyphs An array of subglyph descriptors for composite glyphs. There are num_subglyphs elements in there. Currently internal to FreeType. control_data Certain font drivers can also return the control data for a given glyph image (e.g. TrueType bytecode。
bright text too frail on dark backgrounds， even if is not set. This image can later be converted into a bitmap by calling . This function searches the current renderer for the native image's format， the values represent dimensions of the hinted glyph (in case hinting is applicable). Stroking a glyph with an outside border does not increase horiAdvance or vertAdvance; you have to manually adjust these values to account for the added width and height. FreeType doesn't use the VORG table data for CFF fonts because it doesn't have an interface to quickly retrieve the glyph height. The ycoordinate of the vertical origin can be simply computed as vertBearingY + height after loading a glyph. FT_Load_Glyph Defined in FT_FREETYPE_H (freetype/freetype.h). FT_EXPORT( ) FT_Load_Glyph ( face， or render glyph， with code like FT_Load_Glyph( face，right_glyph， and in pixels for fixed-sizes formats. return FreeType error code. 0means success. note Only horizontal layouts (left-to-right right-to-left) are supported by this method. Other layouts，*akerning ); Return the kerning vector between two glyphs of the same face. input face A handle to a source face object. left_glyph The index of the left glyph in the kern pair. right_glyph The index of the right glyph in the kern pair. kern_mode See for more information. Determines the scale and dimension of the returned kerning vector. output akerning The kerning vector. This is either in font units，load_flags | FT_LOAD_TARGET_LIGHT ); FT_Render_Glyph( face-glyph， respectively. The distance units are arbitrarily determined by an adjustable property. note The selected render mode only affects scalable vector glyphs of a font. Embedded bitmaps often have a different pixel mode like . You can use to transform them into 8-bit pixmaps. FT_Get_Kerning Defined in FT_FREETYPE_H (freetype/freetype.h). FT_EXPORT( ) FT_Get_Kerning (face， experimental] If the glyph index maps to an entry in the face's ‘COLR’ table with a ‘CPAL’ palette table (as defined in the OpenType specification)， the glyph bitmap is an alpha coverage bitmap)，0) on the baseline). Of course， meaning that 0xFF/0xFF fraction of that pixel is covered， are out of the scope of this API function they can be implemented through format-specific interfaces. Note that。
the pixels are so small that their chance of being completely covered and therefore completely black are fairly good. On the low-DPI screens， switching between and enforces a lot of recomputation for TrueType fonts。
unless is set when loading the glyph. This field can be important to perform correct WYSIWYG layout. Only relevant for scalable glyphs. advance This shorthand is， FreeType Docs Glyph Retrieval Glyph RetrievalSynopsis The functions and structures collected in this section operate on single glyphs， without the use of bundled metrics tables (for example， using data from AFM files (if attached with or ). Only very few AFM files come with track kerning data; please refer to Adobe's AFM specification for more details. ， the glyph slots are listed through a direct， then converting it into a bitmap that is returned in slot-bitmap. Note that slot-bitmap_left and slot-bitmap_top are also used to specify the position of the bitmap relative to the current pen position (e.g.， this flag is only implemented for TrueType fonts. FT_LOAD_BITMAP_METRICS_ONLY [Since 2.7.1] Request loading of the metrics and bitmap image information of a (possibly embedded) bitmap glyph without allocating or copying the bitmap image data itself. No effect if the target glyph is not a bitmap image. This flag unsets . FT_LOAD_CROP_BITMAP Ignored. Deprecated. FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH Ignored. Deprecated. note By default， errors from the TrueType bytecode engine are not passed to the application if this flag is not set; this might result in partially hinted or distorted glyphs in case a glyph's bytecode is buggy. FT_LOAD_NO_RECURSE Don't load composite glyphs recursively. Instead， you can also decide which hinting algorithm to use. See for details. Note that the auto-hinter needs a valid Unicode cmap (either a native one or synthesized by FreeType) for producing correct results. If a font provides an incorrect mapping (for example， it uses either the horiAdvance or the vertAdvance value of metrics field. format This field indicates the format of the image contained in the glyph slot. Typically 。
while increasingly positive values represent looser track kerning. Value zero means no track kerning. output akerning The kerning in 16.16 fractional points， the library provides hooks to seamlessly integrate an external renderer. See sections ‘’ and ‘’ for more. [Since 2.10， so it would output kerning values of zero; though if the right-to-left font used only advances in GPOS pair positioning， using FT_LOAD_NO_SCALE usually yields meaningless outlines because the subglyphs must be scaled and positioned with hinting instructions. This can be solved by loading the font without FT_LOAD_NO_SCALE and setting the character size to font-units_per_EM. FT_LOAD_NO_HINTING Disable hinting. This generally generates ‘blurrier’ bitmap glyphs when the glyphs are rendered in any of the anti-aliased modes. See also the note below. This flag is implied by . FT_LOAD_RENDER Call after the glyph is loaded. By default， you must apply these delta values! Otherwise you will experience far too large inter-glyph spacing at small rendering sizes in most cases. Note that it doesn't harm to use the above code for other hinting modes also， it is possible to use the light hinting algorithm and have the results rendered in horizontal LCD pixel mode， then this API could output kerning values for it， or ...origin_x += slot-advance.x; endfor If you use strong auto-hinting， pair-wise kerning feature from the GPOS table (with TT_CONFIG_OPTION_GPOS_KERNING enabled)， the transformed (hinted) advance width for the glyph， ， each time you call or ，， etc). return FreeType error code. 0means success. note For proper scaling and hinting， as is done by FreeType's new CFF engine or Microsoft's ClearType font renderer. This preserves inter-glyph spacing in horizontal text. The snapping is done either by the native font driver， the functionality may differ for fonts with GPOS tables vs. kern tables. For GPOS， using the format. [Since 2.12] If the glyph index maps to an entry in the face's ‘SVG ’ table， or ...compute kern between current and next glyphand add it to `origin_xorigin_x += slot-advance.x;origin_x += slot-lsb_delta - slot-rsb_delta; endfor Here is another small pseudo code fragment that shows how to use lsb_delta and rsb_delta to improve integer positioning of glyphs: FT_GlyphSlot slot= face-glyph; FT_Posorigin_x= 0; FT_Posprev_rsb_delta = 0;for all glyphs docompute kern between current and previous glyphand add it to `origin_xload glyph with `FT_Load_Glyphif ( prev_rsb_delta - slot-lsb_delta 32 )origin_x -= 64;else if ( prev_rsb_delta - slot-lsb_delta -31 )origin_x += 64;prev_rsb_delta = slot-rsb_delta;save glyph image， and those values are not always consistent across various font formats. FT_LOAD_FORCE_AUTOHINT Prefer the auto-hinter over the font's native hinter. See also the note below. FT_LOAD_PEDANTIC Make the font driver perform pedantic verifications during glyph loading and hinting. This is mostly used to detect broken glyphs in fonts. By default， the coverage map says 50% black， if the driver itself and the font support it。
FT_Err_Invalid_Argument is returned for invalid CID values (that is， the active object owned by the face has to be meaningfully initialized by calling before this function。
for CID values that don't have a corresponding glyph in the font). See the discussion of the flag for more details. If you receive FT_Err_Glyph_Too_Big， though FreeType does not support the more advanced GPOS layout features; use a library like HarfBuzz for those instead. If a font has both a kern table and kern features of a GPOS table， use OVER to blend the two linear colors using the glyph pixel as the alpha value (remember， of which is most important. FT_GlyphSlot Defined in FT_FREETYPE_H (freetype/freetype.h). typedef struct FT_GlyphSlotRec_* FT_GlyphSlot ; A handle to a given glyph slot. A slot is a container that can hold any of the glyphs contained in its parent face. In other words， rotated LCD displays， try getting the glyph outline at EM size， then scale it manually and fill it as a graphics operation. FT_LOAD_XXX Defined in FT_FREETYPE_H (freetype/freetype.h). # define 0x0# define ( 1L 0 )# define ( 1L 1 )# define ( 1L 2 )# define ( 1L 3 )# define ( 1L 4 )# define ( 1L 5 )# define ( 1L 6 )# define ( 1L 7 )# define ( 1L 9 )# define ( 1L 10 )# define ( 1L 11 )# define ( 1L 12 )# define ( 1L 13 )# define ( 1L 14 )# define ( 1L 15 ) /* Bits 16-19 are used by `FT_LOAD_TARGET_` */# define ( 1L 20 )# define ( 1L 21 )# define ( 1L 22 )# define ( 1L 24 ) A list of bit field constants for to indicate what kind of operations to perform during glyph loading. values FT_LOAD_DEFAULT Corresponding to 0， depending on ， then ‘hinted’ to the pixel grid in order to optimize it. The outline data can be accessed from the glyph slot (see note below). Note that by default the glyph loader doesn't render outlines into bitmaps. The following flags are used to modify this default behaviour to more specific and useful cases. FT_LOAD_NO_SCALE Don't scale the loaded outline glyph but keep it in font units. This flag is also assumed if owned by the face was not properly initialized. This flag implies and ， the mode that matches the used algorithm best). An exception is FT_LOAD_TARGET_MONO since it implies . You can use a hinting algorithm that doesn't correspond to the same rendering mode. As an example。
they are converted to 256-level gray bitmaps， with pre-multiplied color channels. If the flag is not set and color bitmaps are found，。
etc. However， this does not translate to 50% brightness for that pixel on our sRGB and gamma2.2 screens. Due to their non-linearity， scaled to device pixels， verify。
don't use but load the glyph with and scale it， which need to ignore， values are expressed in font units instead. fields width The glyph's width. height The glyph's height. horiBearingX Left side bearing for horizontal layout. horiBearingY Top side bearing for horizontal layout. horiAdvance Advance width for horizontal layout. vertBearingX Left side bearing for vertical layout. vertBearingY Top side bearing for vertical layout. Larger positive values mean further below the vertical glyph origin. vertAdvance Advance height for vertical layout. Positive values mean the glyph has a positive advance downward. note If not disabled with ， be they in outline or bitmap format. fields library A handle to the FreeType library instance this slot belongs to. face A handle to the parent face object. next In some cases (like some font tools)， finding the relevant renderer， 0 );save glyph image。
whether to hint the outline， it does. 0% and 100% brightness are the same things in linear and non-linear space， or edit those tables. Currently， upwards y coordinates being positive . outline The outline descriptor for the current glyph image if its format is . Once a glyph is loaded， which this API does not support，glyph_index。
assigning the character code U+005A， the advance value in the structure is set to the vertAdvance value of the metrics field. In case doesn't return true，} FT_Kerning_Mode ;/* these constants are deprecated; use the corresponding */ /* ` FT_Kerning_Mode ` values instead*/# define ft_kerning_default # define ft_kerning_unfitted # define ft_kerning_unscaled An enumeration to specify the format of kerning values returned by . values FT_KERNING_DEFAULT Return grid-fitted kerning distances in 26.6 fractional pixels. FT_KERNING_UNFITTED Return un-grid-fitted kerning distances in 26.6 fractional pixels. FT_KERNING_UNSCALED Return the kerning vector in original font units. note FT_KERNING_DEFAULT returns full pixel values; it also makes FreeType heuristically scale down kerning distances at small ppem values so that they don't become too big. Both FT_KERNING_DEFAULT and FT_KERNING_UNFITTED use the current horizontal scaling factor (as set e.g. with ) to convert font units to pixels. FT_Get_Track_Kerning Defined in FT_FREETYPE_H (freetype/freetype.h). FT_EXPORT( ) FT_Get_Track_Kerning (face，* akerning ); Return the track kerning for a given face object at a given size. input face A handle to a source face object. point_size The point size in 16.16 fractional points. degree The degree of tightness. Increasingly negative values represent tighter track kerning， but on our low-DPI screens with all the gray shades。
TrueType-like metrics are used to make this mode behave similarly as in unpatched FreeType versions between 2.4.6 and 2.7.1 (inclusive). FT_LOAD_TARGET_MONO Strong hinting algorithm that should only be used for monochrome output. The result is probably unpleasant if the glyph is rendered in non-monochrome modes. Note that for outline fonts only the TrueType font driver has proper monochrome hinting support，kern_mode。
you should stick with one rendering mode. For example， have the format， the pixel is made 50% black (50% bright or a middle shade of grey). 0% covered means 0% black (100% bright or white). On high-DPI screens like on smartphones and tablets， it is possible to get fractional advance widths for subpixel positioning (which is recommended to use). If configuration option AF_CONFIG_OPTION_TT_SIZE_METRICS is active，， or pixels for scalable formats， or render glyph， you shouldn't use this flag currently. Reason is that in this case vertical metrics get synthesized， it must not be freed. [Since 2.10.1] If is set， a previous call of with flag makes FT_Render_Glyph provide a default blending of colored glyph layers associated with the current glyph slot (provided the font contains such layers) instead of rendering the glyph slot's outline. This is an experimental feature; see for more information. return FreeType error code. 0means success. note When FreeType outputs a bitmap of a glyph， several glyph slots per face object can be a good thing. As this is rare， using the lsb_delta and rsb_delta fields of ， fractional pixels (26.6 format)， use instead. FT_LOAD_TARGET_LIGHT A lighter hinting algorithm for gray-level modes. Many generated glyphs are fuzzier but better resemble their original shape. This is achieved by snapping glyphs to the pixel grid only vertically (Y-axis)， origin_x 63， etc.). It produces 8-bit bitmaps that are 3 times the height of the original glyph outline in pixels and use the mode. FT_RENDER_MODE_SDF The positive (unsigned) 8-bit bitmap values can be converted to the single-channel signed distance field (SDF) by subtracting 128， whether to load bitmaps or not， the glyph's metrics， provided the TTFs contain hints for B/W rendering (which most fonts no longer provide). If these conditions are not met it is very likely that you get ugly results at smaller sizes. FT_LOAD_TARGET_LCD A variant of optimized for horizontally decimated LCD displays. FT_LOAD_TARGET_LCD_V A variant of optimized for vertically decimated LCD displays. note You should use only one of the FT_LOAD_TARGET_XXX values in your load_flags. They can't be ORed. If is also set， for example. The loaded glyph may be transformed. See for the details. For subsetted CID-keyed fonts，， the bitmap contains 0xFF at that pixel， and colored text on colored background (for example， load the associated SVG document from this table and set the format field of to ([since 2.13.1] provided is not set). Note that FreeType itself can't render SVG documents; however， coordinates (0， the ‘hdmx’ table in TrueType fonts). This flag is mainly used by font validating or font editing applications， optimized for standard gray-level rendering. For monochrome output。
indicating the signed distance from the grid position to the nearest outline. values FT_RENDER_MODE_NORMAL Default render mode; it corresponds to 8-bit anti-aliased bitmaps. FT_RENDER_MODE_LIGHT This is equivalent to . It is only defined as a separate value because render modes are also used indirectly to define hinting algorithm selectors. See for details. FT_RENDER_MODE_MONO This mode corresponds to 1-bit bitmaps (with 2 levels of opacity). FT_RENDER_MODE_LCD This mode corresponds to horizontal RGB and BGR subpixel displays like LCD screens. It produces 8-bit bitmaps that are 3 times the width of the original glyph outline in pixels， an outline glyph for TrueType and Type1 formats). [Since 2.9] The prospective bitmap metrics are calculated according to and other flags even for the outline glyph，FT_RENDER_MODE_MAX } FT_Render_Mode ;/* these constants are deprecated; use the corresponding */ /* ` FT_Render_Mode ` values instead*/# define ft_render_mode_normal # define ft_render_mode_mono Render modes supported by FreeType2. Each mode corresponds to a specific type of scanline conversion performed on the outline. For bitmap fonts and embedded bitmaps the bitmap-pixel_mode field in the structure gives the format of the returned bitmap. All modes except use 256 levels of opacity，render_mode ); Convert a given glyph image to a bitmap. It does so by inspecting the glyph image format。
to be uniformly applied between all glyphs. return FreeType error code. 0means success. note Currently， make provide a default blending of the color glyph layers associated with the glyph index， the slot's content is erased by the new glyph data， which is known as the OVER operator. To correctly composite an anti-aliased pixel of a glyph onto a surface， or more sophisticated kernings， etc.). This field is a pointer to such data; it is currently internal to FreeType. control_len This is the length in bytes of the control data. Currently internal to FreeType. other Reserved. lsb_delta The difference between hinted and unhinted left side bearing while auto-hinting is active. Zero otherwise. rsb_delta The difference between hinted and unhinted right side bearing while auto-hinting is active. Zero otherwise. note If is called with default flags (see ) the glyph image is loaded in the glyph slot in its native format (e.g.， the kern table will be used. Also note for right-to-left scripts。
only the Type1 font driver supports track kerning， and unsets . If the font is ‘tricky’ (see for more)， pixely and blotchy on bright background， see section . Then the only difference to gray linear blending is that subpixel-rendered linear blending is done 3times per pixel: red foreground subpixel to red background subpixel and so on for green and blue. FT_Render_Mode Defined in FT_FREETYPE_H (freetype/freetype.h). typedef enum FT_Render_Mode_ {= 0， and which use the mode. FT_RENDER_MODE_LCD_V This mode corresponds to vertical RGB and BGR subpixel displays (like PDA screens， the function returns. The bitmap data can be accessed from the glyph slot (see note below). If no embedded bitmap is searched for or found， i.e.，。
red on green) seems to have dark halos or dirt around it. The situation is especially ugly for diagonal stems like in w glyph shapes where the quality of FreeType's anti-aliasing depends on the correct display of grays. On high-DPI screens where smaller， as expected. To get unrounded font units， if available， whether the outline should be scaled， take the foreground and background colors (e.g.。
in 26.6 fractional pixel format. As specified with ， the following happens: FreeType looks for a bitmap for the glyph corresponding to the face's current size. If one is found， the TrueType bytecode interpreter). You can set to ensure that the auto-hinter is used. values FT_LOAD_TARGET_NORMAL The default hinting algorithm。
glyph_index，point_size。
this doesn't matter， for TrueType and OpenType fonts only， this value is used as the default glyph load operation. In this case， FreeType looks for a scalable outline. If one is found， indicating pixel coverage. Use linear alpha blending and gamma correction to correctly render non-monochrome glyph bitmaps onto a surface; see . The is a special render mode that uses up to 256 distance values，， but it would use left_glyph to mean the first glyph for that case. Whereas kern tables are always advance-only and always store the left glyph first. Use to find out whether a font has data that can be extracted with FT_Get_Kerning. FT_Kerning_Mode Defined in FT_FREETYPE_H (freetype/freetype.h). typedef enum FT_Kerning_Mode_ {= 0， however， LATIN CAPITAL LETTERZ， which is slow. Another reason is caching: Selecting a different mode usually causes changes in both the outlines and the rasterized bitmaps; it is thus necessary to empty the cache after a mode switch to avoid false hits. FT_Render_Glyph Defined in FT_FREETYPE_H (freetype/freetype.h). FT_EXPORT( ) FT_Render_Glyph (slot， and invoking it. inout slot A handle to the glyph slot containing the image to convert. input render_mode The render mode used to render the glyph image into a bitmap. See for a list of possible values. If is used， FT_RENDER_MODE_LCD ); In general， using the same bitmap format as embedded color bitmap images. This is mainly for convenience and works only for glyphs in ‘COLR’ v0 tables. There is no rendering support for ‘COLR’ v1 (with the exception of v1 tables that exclusively use v0 features)! You need a graphics library like Skia or Cairo to interpret the graphics commands stored in v1 tables. For full control of color layers use and FreeType's color functions like instead of setting for rendering so that the client application can handle blending by itself. FT_LOAD_NO_SVG [Since 2.13.1] Ignore SVG glyph data when loading. FT_LOAD_COMPUTE_METRICS [Since 2.6.1] Compute glyph metrics from the glyph data， the font driver fills the num_subglyph and subglyphs values of the glyph slot; it also sets glyph-format to . The description of subglyphs can then be accessed with . Don't use this flag for retrieving metrics information since some font drivers only return rudimentary data. This flag implies and . FT_LOAD_IGNORE_TRANSFORM Ignore the transform matrix set by . FT_LOAD_MONOCHROME This flag is used with to indicate that you want to render an outline glyph to a 1-bit monochrome bitmap glyph， with the positive and negative results corresponding to the inside and the outside of a glyph contour， just all the shades in-between aren't. The blending function for placing text over a background is dst = alpha * src + (1 - alpha) * dst ， distorted， and apply inverse gamma to the blended pixel and write it back to the image. Internal testing at Adobe found that a target inverse gamma of1.8 for step3 gives good results across a wide range of displays with an sRGB gamma curve or a similar one. This process can cost performance. There is an approximation that does not need to know about the background color; see https://web.archive.org/web/20211019204945/https://bel.fi/alankila/lcd/ and https://web.archive.org/web/20210211002939/https://bel.fi/alankila/lcd/alpcor.html for details. ATTENTION : Linear blending is even more important when dealing with subpixel-rendered glyphs to prevent color-fringing! A subpixel-rendered glyph must first be filtered with a filter that gives equal weight to the three color primaries and does not exceed a sum of 0x100。
unless is set when loading the glyph. This field can be important to perform correct WYSIWYG layout. Only relevant for scalable glyphs. linearVertAdvance The advance height of the unhinted glyph. Its value is expressed in 16.16 fractional pixels， and this translates to a pixel value of 128 when you use 8bits per channel (0-255). However， ( (x) 16 ) 15 ) Return the corresponding to a given value. FT_LOAD_TARGET_XXX Defined in FT_FREETYPE_H (freetype/freetype.h). # define FT_LOAD_TARGET_( x ) ( FT_STATIC_CAST( ， single-linked list using its next field. glyph_index [Since 2.10] The glyph index passed as an argument to while initializing the glyph slot. generic A typeless pointer unused by the FreeType library or any of its drivers. It can be used by client applications to link their own data to each glyph slot object. metrics The metrics of the last loaded glyph in the slot. The returned values depend on the last load flags (see the API function) and can be expressed either in 26.6 fractional pixels or font units. Note that even when the glyph image is transformed， in sRGB space) and apply gamma to get them in a linear space， they dwell longer in the darks and only a pixel value of about 186 results in 50% brightness 128 ends up too dark on both bright and dark backgrounds. The net result is that dark text looks burnt-out。
FreeType tries to handle broken fonts also. In particular， right-to-left fonts typically use both a placement offset and an advance for pair positioning， Type 1 charstrings， the glyph is rendered in the corresponding mode (i.e.，，load_flags ); Load a glyph into the glyph slot of a face object. inout face A handle to the target face object where the glyph is loaded. input glyph_index The index of the glyph in the font file. For CID-keyed fonts (either in PS or in CFF format) this argument specifies the CID value. load_flags A flag indicating what to load for this glyph. The flags can be used to control the glyph loading process (e.g.， outline can be transformed，degree。
to a glyph depicting a mathematical integral sign)， or by the auto-hinter. Advance widths are rounded to integer values; however， emboldened， its image (bitmap or outline)。
with 8 pixels packed into each byte of the bitmap data. Note that this has no effect on the hinting algorithm used. You should rather use so that the monochrome-optimized hinting algorithm is used. FT_LOAD_LINEAR_DESIGN Keep linearHoriAdvance and linearVertAdvance fields of in font units. See for details. FT_LOAD_NO_AUTOHINT Disable the auto-hinter. See also the note below. FT_LOAD_COLOR Load colored glyphs. FreeType searches in the following order; there are slight differences depending on the font format. [Since 2.5] Load embedded color bitmap images (provided is not set). The resulting color bitmaps， more or less: returns FT_Err_Invalid_Argument if the face contains a bitmap strike for the given size (or the strike selected by ) but there is no glyph in the strike. Note that this load flag was part of FreeType since version 2.0.6 but previously tagged as internal. FT_LOAD_VERTICAL_LAYOUT Load the glyph for vertical text layout. In particular。
it really outputs an alpha coverage map. If a pixel is completely covered by a filled-in outline， the glyph is rendered in mode. This can be overridden by or . This flag is unset by . FT_LOAD_NO_BITMAP Ignore bitmap strikes when loading. Bitmap-only fonts ignore this flag. always sets this flag. FT_LOAD_SBITS_ONLY [Since 2.12] This is the opposite of ， this can extract data from both the kern table and the basic， then invokes it. The renderer is in charge of transforming the native image through the slot's face transformation fields， the auto-hinter might produce useless results. FT_LOAD_TARGET_MODE Defined in FT_FREETYPE_H (freetype/freetype.h). # define FT_LOAD_TARGET_MODE ( x )\FT_STATIC_CAST( ， but other values are possible. bitmap This field is used as a bitmap descriptor. Note that the address and content of the bitmap buffer can change between calls of and a few other functions. bitmap_left The bitmap's left bearing expressed in integer pixels. bitmap_top The bitmap's top bearing expressed in integer pixels. This is the distance from the baseline to the top-most glyph scanline， it is loaded from the font file， or ， fully black pixels reign supreme， and other control information. also See for the publicly accessible glyph fields. FT_GlyphSlotRec Defined in FT_FREETYPE_H (freetype/freetype.h). typedef struct FT_GlyphSlotRec_ {library;face;next;glyph_index; /* new in 2.10; was reserved previously */generic;metrics;linearHoriAdvance;linearVertAdvance;advance;format;bitmap;bitmap_left;bitmap_top;outline;num_subglyphs;subglyphs; void *control_data; long control_len;lsb_delta;rsb_delta; void *other;internal; } FT_GlyphSlotRec ; FreeType root glyph slot class structure. A glyph slot is a container where individual glyphs can be loaded， outline coordinates of OpenType Font Variations for a selected instance are internally handled as 26.6 fractional font units but returned as (rounded) integers，left_glyph， meaning the pixel is 100% black (or 0% bright). If a pixel is only 50% covered (value 0x80)， slot-format is also changed to . Here is a small pseudo code fragment that shows how to use lsb_delta and rsb_delta to do fractional positioning of glyphs: FT_GlyphSlot slot= face-glyph; FT_Posorigin_x = 0;for all glyphs doload glyph with `FT_Load_GlyphFT_Outline_Translate( slot-outline， (x) 15 ) 16 )# define FT_LOAD_TARGET_( )# define FT_LOAD_TARGET_( )# define FT_LOAD_TARGET_( )# define FT_LOAD_TARGET_()# define FT_LOAD_TARGET_( ) A list of values to select a specific hinting algorithm for the hinter. You should OR one of these values to your load_flags when calling . Note that a font's native hinters may ignore the hinting algorithm you have specified (e.g.， hinting is enabled and the font's native hinter (see ) is preferred over the auto-hinter. You can disable hinting by setting or change the precedence by setting . You can also set in case you don't want the auto-hinter to be used at all. See the description of for a special exception (affecting only a handful of Asian fonts). Besides deciding which hinter to use， the situation is different. The pixels are too large for most of the details of a glyph and shades of gray are the norm rather than the exception. This is relevant because all our screens have a second problem: they are not linear. 1+1 is not2. Twice the value does not result in twice the brightness. When a pixel is only 50% covered。