UnicodeFontDefs.h File Reference

contains font rendering structures both for AdafruitGFX fonts and TcUnicode fonts More...

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Classes
struct	GFXglyph
struct	GFXfont
struct	UnicodeFontGlyph
struct	UnicodeFontBlock
struct	UnicodeFont

Typedefs
typedef uint32_t	bitmap_size_t

Enumerations
enum	BitmapFormat : uint8_t { TCFONT_ONE_BIT_PER_PIXEL }

Detailed Description

contains font rendering structures both for AdafruitGFX fonts and TcUnicode fonts

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Class Documentation

GFXglyph

struct GFXglyph

The adafruit font glyph format, each letter in the font is represented by a GFXglyph in an array. This indicates how to read the bitmap and process it, the width and height are related to the bitmap, but the bitmap may not take up the full area, the xAdvance is how far to move in the x dimension after rendering the bitmap, the x and y offsets tell the renderer where to start drawing the bit. With these fonts, the y start point is always the baseline.

Class Members
uint16_t	bitmapOffset	Pointer into GFXfont->bitmap.
uint8_t	height	Bitmap dimensions in pixels.
uint8_t	width	Bitmap dimensions in pixels.
uint8_t	xAdvance	Distance to advance cursor (x axis)
int8_t	xOffset	X dist from cursor pos to UL corner.
int8_t	yOffset	Y dist from cursor pos to UL corner.

GFXfont

struct GFXfont

This represents an adafruit font, it holds the bitmap data for all glyphs, and also includes and array of glyphs, these are sequential characters from first through to last. Lastly, the yAdvance indicates how far to go for a new line.

Class Members
uint8_t *	bitmap	Glyph bitmaps, concatenated.
uint16_t	first	ASCII extents (first char)
GFXglyph *	glyph	Glyph array.
uint16_t	last	ASCII extents (last char)
uint8_t	yAdvance	Newline distance (y axis)

UnicodeFontGlyph

struct UnicodeFontGlyph

The TcUnicode glyph format is very similar to the adafruit glyph format, other than some small differences to make unicode handling easier. The biggest difference is the relativeChar support, so it is possible to skip parts of a font that are not needed. This char code is relative to the unicode block. The bit map offset has been adjusted to 17 bits, to allow each block to have 128K of bitmaps.

This glyph data indicates how to read the bitmap and process it, the width and height are related to the bitmap, but the bitmap may not take up the full area, the xAdvance is how far to move in the x dimension after rendering the bitmap, the x and y offsets tell the renderer where to start drawing the bit. With these fonts, the y start point is always the baseline.

Class Members
uint8_t	height	height of the bitmap in pixels
bitmap_size_t	relativeBmpOffset	offset into the bitmap array
uint16_t	relativeChar	The character number in the array
uint8_t	width	width of the bitmap in pixels
uint8_t	xAdvance	how far to advance in the x dimension
int8_t	xOffset	the x offset from the UL corner
int8_t	yOffset	the y offset from the UL corner, usually negative

UnicodeFontBlock

struct UnicodeFontBlock

A unicode block is a range of character akin to a code page. In this structure we store the bitmaps and glyphs that are associated with the block range. This allows us to be more efficient with memory overall. The char nums in a glyph are actually calculated by startingId + charNum

Class Members
const uint8_t *	bitmap	the array of bitmaps for each letter
const UnicodeFontGlyph *	glyphs	The glyphs within this block
uint16_t	numberOfPoints	The number of points in this block
uint32_t	startingNum	The starting point for this block, all glyph entries are an offset from this

UnicodeFont

struct UnicodeFont

This represents the whole font, and is passed to an TcUnicode renderer requiring a font. It is basically an array of blocks sorted by starting code in reverse order. It also has instructions on how to process the bitmap structure for future improvements, and the yAdvance.

Class Members
BitmapFormat	bitmapFormat
uint16_t	numberOfBlocks	the number of items
const UnicodeFontBlock *	unicodeBlocks	the array of unicode glyphs
uint8_t	yAdvance	the height of each line

Enumeration Type Documentation

BitmapFormat

enum BitmapFormat : uint8_t

Indicates how to read the pixel map within the font. In future I plan to support at least four greyscale levels which allows basic anti-aliasing, and if thre is demand fonts with multiple palette colours, but at the moment only one bit per pixel is supported.