libui/ui_attrstr.h

259 lines
11 KiB
C

// uiAttributedString represents a string of UTF-8 text that can
// optionally be embellished with formatting attributes. libui
// provides the list of formatting attributes, which cover common
// formatting traits like boldface and color as well as advanced
// typographical features like superscripts and small caps.
// These attributes can be combined in a variety of ways.
//
// In addition, uiAttributedString provides facilities for moving
// between grapheme clusters, which represent a character
// from the point of view of the end user. The cursor of a text editor
// is always placed on a grapheme boundary, so you can use these
// features to move the cursor left or right by one "character".
//
// uiAttributedString does not provide enough information to be able
// to draw itself onto a uiDrawContext or respond to user actions.
// In order to do that, you'll need to use a uiDrawTextLayout, which
// is built from the combination of a uiAttributedString and a set of
// layout-specific properties.
typedef struct uiAttributedString uiAttributedString;
// Note: where you say "1 = on", any nonzero value means "on". (TODO)
// TODO ok, we need to figure out what to do about pointer objects: do we copy them or do we keep them safe? especially since we merge attributes...
_UI_ENUM(uiAttribute) {
uiAttributeFamily,
uiAttributeSize, // use Double
uiAttributeWeight,
uiAttributeItalic,
uiAttributeStretch,
uiAttributeColor, // use R, G, B, A
uiAttributeBackground, // use R, G, B, A
uiAttributeUnderline, // enum uiDrawUnderlineStyle
// TODO document that the color in the case we don't specify it is the text color
uiAttributeUnderlineColor, // enum uiDrawUnderlineColor
// TODO note that for the purpose of uiAttributedString two sets of features are only the same (and thus their attributes are merged) only if the pointers are the same; whether the tag sets are the same only become relevant to uiDrawTextLayout
uiAttributeFeatures, // object of type uiOpenTypeFeatures
};
_UI_ENUM(uiDrawUnderlineStyle) {
uiDrawUnderlineStyleNone,
uiDrawUnderlineStyleSingle,
uiDrawUnderlineStyleDouble,
uiDrawUnderlineStyleSuggestion, // wavy or dotted underlines used for spelling/grammar checkers
};
_UI_ENUM(uiDrawUnderlineColor) {
uiDrawUnderlineColorCustom, // also use R/G/B/A fields
uiDrawUnderlineColorSpelling,
uiDrawUnderlineColorGrammar,
uiDrawUnderlineColorAuxiliary, // for instance, the color used by smart replacements on OS X
};
// TODO rename?
typedef struct uiOpenTypeFeatures uiOpenTypeFeatures;
// TODO pass the feature set?
typedef int (*uiOpenTypeFeaturesForEachFunc)(char a, char b, char c, char d, uint32_t value, void *data);
// TODO detailed constructor?
_UI_EXTERN uiOpenTypeFeatures *uiNewOpenTypeFeatures(void);
_UI_EXTERN void uiFreeOpenTypeFeatures(uiOpenTypeFeatures *otf);
// TODO put above Free?
// TODO Copy instead of Clone?
_UI_EXTERN uiOpenTypeFeatures *uiOpenTypeFeaturesClone(uiOpenTypeFeatures *otf);
_UI_EXTERN void uiOpenTypeFeaturesAdd(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t value);
_UI_EXTERN void uiOpenTypeFeaturesRemove(uiOpenTypeFeatures *otf, char a, char b, char c, char d);
_UI_EXTERN int uiOpenTypeFeaturesGet(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t *value);
_UI_EXTERN void uiOpenTypeFeaturesForEach(uiOpenTypeFeatures *otf, uiOpenTypeFeaturesForEachFunc f, void *data);
_UI_EXTERN int uiOpenTypeFeaturesEqual(uiOpenTypeFeatures *a, uiOpenTypeFeatures *b);
typedef struct uiAttributeSpec uiAttributeSpec;
struct uiAttributeSpec {
uiAttribute Type;
uintptr_t Value;
double Double;
double R;
double G;
double B;
double A;
};
// TODO name the foreach return values
typedef int (*uiAttributedStringForEachAttributeFunc)(uiAttributedString *s, uiAttributeSpec *spec, size_t start, size_t end, void *data);
// @role uiAttributedString constructor
// uiNewAttributedString() creates a new uiAttributedString from
// initialString. The string will be entirely unattributed.
_UI_EXTERN uiAttributedString *uiNewAttributedString(const char *initialString);
// @role uiAttributedString destructor
// uiFreeAttributedString() destroys the uiAttributedString s.
_UI_EXTERN void uiFreeAttributedString(uiAttributedString *s);
// uiAttributedStringString() returns the textual content of s as a
// '\0'-terminated UTF-8 string. The returned pointer is valid until
// the next change to the textual content of s.
_UI_EXTERN const char *uiAttributedStringString(uiAttributedString *s);
// uiAttributedStringLength() returns the number of UTF-8 bytes in
// the textual content of s, excluding the terminating '\0'.
_UI_EXTERN size_t uiAttributedStringLen(uiAttributedString *s);
_UI_EXTERN void uiAttributedStringAppendUnattributed(uiAttributedString *s, const char *str);
_UI_EXTERN void uiAttributedStringInsertAtUnattributed(uiAttributedString *s, const char *str, size_t at);
_UI_EXTERN void uiAttributedStringDelete(uiAttributedString *s, size_t start, size_t end);
_UI_EXTERN size_t uiAttributedStringNumGraphemes(uiAttributedString *s);
_UI_EXTERN size_t uiAttributedStringByteIndexToGrapheme(uiAttributedString *s, size_t pos);
_UI_EXTERN size_t uiAttributedStringGraphemeToByteIndex(uiAttributedString *s, size_t pos);
_UI_EXTERN void uiAttributedStringSetAttribute(uiAttributedString *s, uiAttributeSpec *spec, size_t start, size_t end);
_UI_EXTERN void uiAttributedStringForEachAttribute(uiAttributedString *s, uiAttributedStringForEachAttributeFunc f, void *data);
typedef struct uiDrawFontDescriptor uiDrawFontDescriptor;
// TODO Minimum == 1? IIRC there is at least one font on OS X that actually has a weight of 0
// TODO Maximum == 999? IIRC there is at least one font on OS X that actually has a weight of 1000
_UI_ENUM(uiDrawTextWeight) {
uiDrawTextWeightMinimum = 0,
uiDrawTextWeightThin = 100,
uiDrawTextWeightUltraLight = 200,
uiDrawTextWeightLight = 300,
uiDrawTextWeightBook = 350,
uiDrawTextWeightNormal = 400,
uiDrawTextWeightMedium = 500,
uiDrawTextWeightSemiBold = 600,
uiDrawTextWeightBold = 700,
uiDrawTextWeightUltraBold = 800,
uiDrawTextWeightHeavy = 900,
uiDrawTextWeightUltraHeavy = 950,
uiDrawTextWeightMaximum = 1000,
};
_UI_ENUM(uiDrawTextItalic) {
uiDrawTextItalicNormal,
uiDrawTextItalicOblique,
uiDrawTextItalicItalic,
};
// TODO realign this so that Normal == 0?
_UI_ENUM(uiDrawTextStretch) {
uiDrawTextStretchUltraCondensed,
uiDrawTextStretchExtraCondensed,
uiDrawTextStretchCondensed,
uiDrawTextStretchSemiCondensed,
uiDrawTextStretchNormal,
uiDrawTextStretchSemiExpanded,
uiDrawTextStretchExpanded,
uiDrawTextStretchExtraExpanded,
uiDrawTextStretchUltraExpanded,
};
struct uiDrawFontDescriptor {
char *Family;
double Size;
uiDrawTextWeight Weight;
uiDrawTextItalic Italic;
uiDrawTextStretch Stretch;
};
typedef struct uiDrawTextLayout uiDrawTextLayout;
typedef struct uiDrawTextLayoutParams uiDrawTextLayoutParams;
typedef struct uiDrawTextLayoutLineMetrics uiDrawTextLayoutLineMetrics;
// TODO drop the Layout from this?
_UI_ENUM(uiDrawTextLayoutAlign) {
uiDrawTextLayoutAlignLeft,
uiDrawTextLayoutAlignCenter,
uiDrawTextLayoutAlignRight,
};
struct uiDrawTextLayoutParams {
uiAttributedString *String;
uiDrawFontDescriptor *DefaultFont;
double Width;
uiDrawTextLayoutAlign Align;
};
// Height will equal ParagraphSpacingBefore + LineHeightSpace + Ascent + Descent + Leading + LineSpacing + ParagraphSpacing.
// The above values are listed in vertical order, from top to bottom.
// Ascent + Descent + Leading will give you the typographic bounds
// of the text. BaselineY is the boundary between Ascent and Descent.
// X, Y, and BaselineY are all in the layout's coordinate system, so the
// start point of the baseline will be at (X, BaselineY). All values are
// nonnegative.
struct uiDrawTextLayoutLineMetrics {
// This describes the overall bounding box of the line.
double X;
double Y;
double Width;
double Height;
// This describes the typographic bounds of the line.
double BaselineY;
double Ascent;
double Descent;
double Leading;
// This describes any additional whitespace.
// TODO come up with better names for these.
double ParagraphSpacingBefore;
double LineHeightSpace;
double LineSpacing;
double ParagraphSpacing;
// TODO trailing whitespace?
};
// TODO
// - allow creating a layout out of a substring
// - allow marking compositon strings
// - allow marking selections, even after creation
// - add the following functions:
// - uiDrawTextLayoutHeightForWidth() (returns the height that a layout would need to be to display the entire string at a given width)
// - uiDrawTextLayoutRangeForSize() (returns what substring would fit in a given size)
// - uiDrawTextLayoutNewWithHeight() (limits amount of string used by the height)
// - some function to fix up a range (for text editing)
_UI_EXTERN uiDrawTextLayout *uiDrawNewTextLayout(uiDrawTextLayoutParams *params);
_UI_EXTERN void uiDrawFreeTextLayout(uiDrawTextLayout *tl);
_UI_EXTERN void uiDrawText(uiDrawContext *c, uiDrawTextLayout *tl, double x, double y);
_UI_EXTERN void uiDrawTextLayoutExtents(uiDrawTextLayout *tl, double *width, double *height);
_UI_EXTERN int uiDrawTextLayoutNumLines(uiDrawTextLayout *tl);
_UI_EXTERN void uiDrawTextLayoutLineByteRange(uiDrawTextLayout *tl, int line, size_t *start, size_t *end);
_UI_EXTERN void uiDrawTextLayoutLineGetMetrics(uiDrawTextLayout *tl, int line, uiDrawTextLayoutLineMetrics *m);
// TODO number of lines visible for clipping rect, range visible for clipping rect?
// TODO rewrite all this documentation
// uiDrawTextLayoutHitTest() returns the byte offset and line closest
// to the given point. The point is relative to the top-left of the layout.
// If the point is outside the layout itself, the closest point is chosen;
// this allows the function to be used for cursor positioning with the
// mouse. Do keep the returned line in mind if used in this way; the
// user might click on the end of a line, at which point the cursor
// might be at the trailing edge of the last grapheme on the line
// (subject to the operating system's APIs).
_UI_EXTERN void uiDrawTextLayoutHitTest(uiDrawTextLayout *tl, double x, double y, size_t *pos, int *line);
// uiDrawTextLayoutByteLocationInLine() returns the point offset
// into the given line that the given byte position stands. This is
// relative to the line's X position (as returned by
// uiDrawTextLayoutLineGetMetrics()), which in turn is relative to
// the top-left of the layout. This function can be used for cursor
// positioning: if start and end are the start and end of the line
// (as returned by uiDrawTextLayoutLineByteRange()), you will get
// the correct offset, even if pos is at the end of the line. If pos is not
// in the range [start, end], a negative value will be returned,
// indicating you need to move the cursor to another line.
// TODO make sure this works right for right-aligned and center-aligned lines and justified lines and RTL text
_UI_EXTERN double uiDrawTextLayoutByteLocationInLine(uiDrawTextLayout *tl, size_t pos, int line);
_UI_EXTERN void uiDrawCaret(uiDrawContext *c, double x, double y, uiDrawTextLayout *layout, size_t pos, int *line);
// TODO allow blinking
typedef struct uiFontButton uiFontButton;
#define uiFontButton(this) ((uiFontButton *) (this))
_UI_EXTERN void uiFontButtonFont(uiFontButton *b, uiDrawFontDescriptor *desc);
// TOOD SetFont, mechanics
_UI_EXTERN void uiFontButtonOnChanged(uiFontButton *b, void (*f)(uiFontButton *, void *), void *data);
_UI_EXTERN uiFontButton *uiNewFontButton(void);