libui/ui.h

// 6 april 2015

// TODO add a uiVerifyControlType() function that can be used by control implementations to verify controls

#ifndef __LIBUI_UI_H__
#define __LIBUI_UI_H__

#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

// TODO add __declspec(dllimport) on windows
#ifndef _UI_EXTERN
#define _UI_EXTERN extern
#endif

// C++ is really really really really really really dumb about enums, so screw that and just make them anonymous
// This has the advantage of being ABI-able should we ever need an ABI...
#define _UI_ENUM(s) typedef unsigned int s; enum

// This constant is provided because M_PI is nonstandard.
// This comes from Go's math.Pi, which in turn comes from http://oeis.org/A000796.
#define uiPi 3.14159265358979323846264338327950288419716939937510582097494459

typedef struct uiInitOptions uiInitOptions;

struct uiInitOptions {
	size_t Size;
};

_UI_EXTERN const char *uiInit(uiInitOptions *options);
_UI_EXTERN void uiUninit(void);
_UI_EXTERN void uiFreeInitError(const char *err);

_UI_EXTERN void uiMain(void);
_UI_EXTERN void uiQuit(void);

_UI_EXTERN void uiQueueMain(void (*f)(void *data), void *data);

_UI_EXTERN void uiOnShouldQuit(int (*f)(void *data), void *data);

_UI_EXTERN void uiFreeText(char *text);

typedef struct uiControl uiControl;

struct uiControl {
	uint32_t Signature;
	uint32_t OSSignature;
	uint32_t TypeSignature;
	void (*Destroy)(uiControl *);
	uintptr_t (*Handle)(uiControl *);
	uiControl *(*Parent)(uiControl *);
	void (*SetParent)(uiControl *, uiControl *);
	int (*Toplevel)(uiControl *);
	int (*Visible)(uiControl *);
	void (*Show)(uiControl *);
	void (*Hide)(uiControl *);
	int (*Enabled)(uiControl *);
	void (*Enable)(uiControl *);
	void (*Disable)(uiControl *);
};
// TOOD add argument names to all arguments
#define uiControl(this) ((uiControl *) (this))
_UI_EXTERN void uiControlDestroy(uiControl *);
_UI_EXTERN uintptr_t uiControlHandle(uiControl *);
_UI_EXTERN uiControl *uiControlParent(uiControl *);
_UI_EXTERN void uiControlSetParent(uiControl *, uiControl *);
_UI_EXTERN int uiControlToplevel(uiControl *);
_UI_EXTERN int uiControlVisible(uiControl *);
_UI_EXTERN void uiControlShow(uiControl *);
_UI_EXTERN void uiControlHide(uiControl *);
_UI_EXTERN int uiControlEnabled(uiControl *);
_UI_EXTERN void uiControlEnable(uiControl *);
_UI_EXTERN void uiControlDisable(uiControl *);

_UI_EXTERN uiControl *uiAllocControl(size_t n, uint32_t OSsig, uint32_t typesig, const char *typenamestr);
_UI_EXTERN void uiFreeControl(uiControl *);

// TODO make sure all controls have these
_UI_EXTERN void uiControlVerifySetParent(uiControl *, uiControl *);
_UI_EXTERN int uiControlEnabledToUser(uiControl *);

_UI_EXTERN void uiUserBugCannotSetParentOnToplevel(const char *type);

typedef struct uiWindow uiWindow;
#define uiWindow(this) ((uiWindow *) (this))
_UI_EXTERN char *uiWindowTitle(uiWindow *w);
_UI_EXTERN void uiWindowSetTitle(uiWindow *w, const char *title);
_UI_EXTERN void uiWindowOnClosing(uiWindow *w, int (*f)(uiWindow *w, void *data), void *data);
_UI_EXTERN void uiWindowSetChild(uiWindow *w, uiControl *child);
_UI_EXTERN int uiWindowMargined(uiWindow *w);
_UI_EXTERN void uiWindowSetMargined(uiWindow *w, int margined);
_UI_EXTERN uiWindow *uiNewWindow(const char *title, int width, int height, int hasMenubar);

typedef struct uiButton uiButton;
#define uiButton(this) ((uiButton *) (this))
_UI_EXTERN char *uiButtonText(uiButton *b);
_UI_EXTERN void uiButtonSetText(uiButton *b, const char *text);
_UI_EXTERN void uiButtonOnClicked(uiButton *b, void (*f)(uiButton *b, void *data), void *data);
_UI_EXTERN uiButton *uiNewButton(const char *text);

typedef struct uiBox uiBox;
#define uiBox(this) ((uiBox *) (this))
_UI_EXTERN void uiBoxAppend(uiBox *b, uiControl *child, int stretchy);
_UI_EXTERN void uiBoxDelete(uiBox *b, uintmax_t index);
_UI_EXTERN int uiBoxPadded(uiBox *b);
_UI_EXTERN void uiBoxSetPadded(uiBox *b, int padded);
_UI_EXTERN uiBox *uiNewHorizontalBox(void);
_UI_EXTERN uiBox *uiNewVerticalBox(void);

typedef struct uiEntry uiEntry;
#define uiEntry(this) ((uiEntry *) (this))
_UI_EXTERN char *uiEntryText(uiEntry *e);
_UI_EXTERN void uiEntrySetText(uiEntry *e, const char *text);
_UI_EXTERN void uiEntryOnChanged(uiEntry *e, void (*f)(uiEntry *e, void *data), void *data);
_UI_EXTERN int uiEntryReadOnly(uiEntry *e);
_UI_EXTERN void uiEntrySetReadOnly(uiEntry *e, int readonly);
_UI_EXTERN uiEntry *uiNewEntry(void);

typedef struct uiCheckbox uiCheckbox;
#define uiCheckbox(this) ((uiCheckbox *) (this))
_UI_EXTERN char *uiCheckboxText(uiCheckbox *c);
_UI_EXTERN void uiCheckboxSetText(uiCheckbox *c, const char *text);
_UI_EXTERN void uiCheckboxOnToggled(uiCheckbox *c, void (*f)(uiCheckbox *c, void *data), void *data);
_UI_EXTERN int uiCheckboxChecked(uiCheckbox *c);
_UI_EXTERN void uiCheckboxSetChecked(uiCheckbox *c, int checked);
_UI_EXTERN uiCheckbox *uiNewCheckbox(const char *text);

typedef struct uiLabel uiLabel;
#define uiLabel(this) ((uiLabel *) (this))
_UI_EXTERN char *uiLabelText(uiLabel *l);
_UI_EXTERN void uiLabelSetText(uiLabel *l, const char *text);
_UI_EXTERN uiLabel *uiNewLabel(const char *text);

typedef struct uiTab uiTab;
#define uiTab(this) ((uiTab *) (this))
_UI_EXTERN void uiTabAppend(uiTab *t, const char *name, uiControl *c);
_UI_EXTERN void uiTabInsertAt(uiTab *t, const char *name, uintmax_t before, uiControl *c);
_UI_EXTERN void uiTabDelete(uiTab *t, uintmax_t index);
_UI_EXTERN uintmax_t uiTabNumPages(uiTab *t);
_UI_EXTERN int uiTabMargined(uiTab *t, uintmax_t page);
_UI_EXTERN void uiTabSetMargined(uiTab *t, uintmax_t page, int margined);
_UI_EXTERN uiTab *uiNewTab(void);

typedef struct uiGroup uiGroup;
#define uiGroup(this) ((uiGroup *) (this))
_UI_EXTERN char *uiGroupTitle(uiGroup *g);
_UI_EXTERN void uiGroupSetTitle(uiGroup *g, const char *title);
_UI_EXTERN void uiGroupSetChild(uiGroup *g, uiControl *c);
_UI_EXTERN int uiGroupMargined(uiGroup *g);
_UI_EXTERN void uiGroupSetMargined(uiGroup *g, int margined);
_UI_EXTERN uiGroup *uiNewGroup(const char *title);

// spinbox/slider rules:
// setting value outside of range will automatically clamp
// initial value is minimum
// complaint if min >= max?

typedef struct uiSpinbox uiSpinbox;
#define uiSpinbox(this) ((uiSpinbox *) (this))
_UI_EXTERN intmax_t uiSpinboxValue(uiSpinbox *s);
_UI_EXTERN void uiSpinboxSetValue(uiSpinbox *s, intmax_t value);
_UI_EXTERN void uiSpinboxOnChanged(uiSpinbox *s, void (*f)(uiSpinbox *s, void *data), void *data);
_UI_EXTERN uiSpinbox *uiNewSpinbox(intmax_t min, intmax_t max);

typedef struct uiProgressBar uiProgressBar;
#define uiProgressBar(this) ((uiProgressBar *) (this))
// TODO uiProgressBarValue()
_UI_EXTERN void uiProgressBarSetValue(uiProgressBar *p, int n);
_UI_EXTERN uiProgressBar *uiNewProgressBar(void);

typedef struct uiSlider uiSlider;
#define uiSlider(this) ((uiSlider *) (this))
_UI_EXTERN intmax_t uiSliderValue(uiSlider *s);
_UI_EXTERN void uiSliderSetValue(uiSlider *s, intmax_t value);
_UI_EXTERN void uiSliderOnChanged(uiSlider *s, void (*f)(uiSlider *s, void *data), void *data);
_UI_EXTERN uiSlider *uiNewSlider(intmax_t min, intmax_t max);

typedef struct uiSeparator uiSeparator;
#define uiSeparator(this) ((uiSeparator *) (this))
_UI_EXTERN uiSeparator *uiNewHorizontalSeparator(void);

typedef struct uiCombobox uiCombobox;
#define uiCombobox(this) ((uiCombobox *) (this))
_UI_EXTERN void uiComboboxAppend(uiCombobox *c, const char *text);
_UI_EXTERN intmax_t uiComboboxSelected(uiCombobox *c);
_UI_EXTERN void uiComboboxSetSelected(uiCombobox *c, intmax_t n);
_UI_EXTERN void uiComboboxOnSelected(uiCombobox *c, void (*f)(uiCombobox *c, void *data), void *data);
_UI_EXTERN uiCombobox *uiNewCombobox(void);
_UI_EXTERN uiCombobox *uiNewEditableCombobox(void);

typedef struct uiRadioButtons uiRadioButtons;
#define uiRadioButtons(this) ((uiRadioButtons *) (this))
_UI_EXTERN void uiRadioButtonsAppend(uiRadioButtons *r, const char *text);
_UI_EXTERN uiRadioButtons *uiNewRadioButtons(void);

typedef struct uiDateTimePicker uiDateTimePicker;
#define uiDateTimePicker(this) ((uiDateTimePicker *) (this))
_UI_EXTERN uiDateTimePicker *uiNewDateTimePicker(void);
_UI_EXTERN uiDateTimePicker *uiNewDatePicker(void);
_UI_EXTERN uiDateTimePicker *uiNewTimePicker(void);

// TODO provide a facility for entering tab stops?
typedef struct uiMultilineEntry uiMultilineEntry;
#define uiMultilineEntry(this) ((uiMultilineEntry *) (this))
_UI_EXTERN char *uiMultilineEntryText(uiMultilineEntry *e);
_UI_EXTERN void uiMultilineEntrySetText(uiMultilineEntry *e, const char *text);
_UI_EXTERN void uiMultilineEntryAppend(uiMultilineEntry *e, const char *text);
_UI_EXTERN void uiMultilineEntryOnChanged(uiMultilineEntry *e, void (*f)(uiMultilineEntry *e, void *data), void *data);
_UI_EXTERN int uiMultilineEntryReadOnly(uiMultilineEntry *e);
_UI_EXTERN void uiMultilineEntrySetReadOnly(uiMultilineEntry *e, int readonly);
_UI_EXTERN uiMultilineEntry *uiNewMultilineEntry(void);
_UI_EXTERN uiMultilineEntry *uiNewNonWrappingMultilineEntry(void);

typedef struct uiMenuItem uiMenuItem;
#define uiMenuItem(this) ((uiMenuItem *) (this))
_UI_EXTERN void uiMenuItemEnable(uiMenuItem *m);
_UI_EXTERN void uiMenuItemDisable(uiMenuItem *m);
_UI_EXTERN void uiMenuItemOnClicked(uiMenuItem *m, void (*f)(uiMenuItem *sender, uiWindow *window, void *data), void *data);
_UI_EXTERN int uiMenuItemChecked(uiMenuItem *m);
_UI_EXTERN void uiMenuItemSetChecked(uiMenuItem *m, int checked);

typedef struct uiMenu uiMenu;
#define uiMenu(this) ((uiMenu *) (this))
_UI_EXTERN uiMenuItem *uiMenuAppendItem(uiMenu *m, const char *name);
_UI_EXTERN uiMenuItem *uiMenuAppendCheckItem(uiMenu *m, const char *name);
_UI_EXTERN uiMenuItem *uiMenuAppendQuitItem(uiMenu *m);
_UI_EXTERN uiMenuItem *uiMenuAppendPreferencesItem(uiMenu *m);
_UI_EXTERN uiMenuItem *uiMenuAppendAboutItem(uiMenu *m);
_UI_EXTERN void uiMenuAppendSeparator(uiMenu *m);
_UI_EXTERN uiMenu *uiNewMenu(const char *name);

_UI_EXTERN char *uiOpenFile(uiWindow *parent);
_UI_EXTERN char *uiSaveFile(uiWindow *parent);
_UI_EXTERN void uiMsgBox(uiWindow *parent, const char *title, const char *description);
_UI_EXTERN void uiMsgBoxError(uiWindow *parent, const char *title, const char *description);

typedef struct uiArea uiArea;
typedef struct uiAreaHandler uiAreaHandler;
typedef struct uiAreaDrawParams uiAreaDrawParams;
typedef struct uiAreaMouseEvent uiAreaMouseEvent;
typedef struct uiAreaKeyEvent uiAreaKeyEvent;

typedef struct uiDrawContext uiDrawContext;

struct uiAreaHandler {
	void (*Draw)(uiAreaHandler *, uiArea *, uiAreaDrawParams *);
	// TODO document that resizes cause a full redraw for non-scrolling areas; implementation-defined for scrolling areas
	void (*MouseEvent)(uiAreaHandler *, uiArea *, uiAreaMouseEvent *);
	// TODO document that on first show if the mouse is already in the uiArea then one gets sent with left=0
	// TODO what about when the area is hidden and then shown again?
	void (*MouseCrossed)(uiAreaHandler *, uiArea *, int left);
	void (*DragBroken)(uiAreaHandler *, uiArea *);
	int (*KeyEvent)(uiAreaHandler *, uiArea *, uiAreaKeyEvent *);
};

#define uiArea(this) ((uiArea *) (this))
// TODO give a better name
// TODO document the types of width and height
_UI_EXTERN void uiAreaSetSize(uiArea *a, intmax_t width, intmax_t height);
// TODO uiAreaQueueRedraw()
_UI_EXTERN void uiAreaQueueRedrawAll(uiArea *a);
_UI_EXTERN void uiAreaScrollTo(uiArea *a, double x, double y, double width, double height);
_UI_EXTERN uiArea *uiNewArea(uiAreaHandler *ah);
_UI_EXTERN uiArea *uiNewScrollingArea(uiAreaHandler *ah, intmax_t width, intmax_t height);

struct uiAreaDrawParams {
	uiDrawContext *Context;

	// TODO document that this is only defined for nonscrolling areas
	double AreaWidth;
	double AreaHeight;

	double ClipX;
	double ClipY;
	double ClipWidth;
	double ClipHeight;
};

typedef struct uiDrawPath uiDrawPath;
typedef struct uiDrawBrush uiDrawBrush;
typedef struct uiDrawStrokeParams uiDrawStrokeParams;
typedef struct uiDrawMatrix uiDrawMatrix;

typedef struct uiDrawBrushGradientStop uiDrawBrushGradientStop;

_UI_ENUM(uiDrawBrushType) {
	uiDrawBrushTypeSolid,
	uiDrawBrushTypeLinearGradient,
	uiDrawBrushTypeRadialGradient,
	uiDrawBrushTypeImage,
};

_UI_ENUM(uiDrawLineCap) {
	uiDrawLineCapFlat,
	uiDrawLineCapRound,
	uiDrawLineCapSquare,
};

_UI_ENUM(uiDrawLineJoin) {
	uiDrawLineJoinMiter,
	uiDrawLineJoinRound,
	uiDrawLineJoinBevel,
};

// this is the default for botoh cairo and Direct2D (in the latter case, from the C++ helper functions)
// Core Graphics doesn't explicitly specify a default, but NSBezierPath allows you to choose one, and this is the initial value
// so we're good to use it too!
#define uiDrawDefaultMiterLimit 10.0

_UI_ENUM(uiDrawFillMode) {
	uiDrawFillModeWinding,
	uiDrawFillModeAlternate,
};

struct uiDrawMatrix {
	double M11;
	double M12;
	double M21;
	double M22;
	double M31;
	double M32;
};

struct uiDrawBrush {
	uiDrawBrushType Type;

	// solid brushes
	double R;
	double G;
	double B;
	double A;

	// gradient brushes
	double X0;		// linear: start X, radial: start X
	double Y0;		// linear: start Y, radial: start Y
	double X1;		// linear: end X, radial: outer circle center X
	double Y1;		// linear: end Y, radial: outer circle center Y
	double OuterRadius;		// radial gradients only
	uiDrawBrushGradientStop *Stops;
	size_t NumStops;
	// TODO extend mode
	// cairo: none, repeat, reflect, pad; no individual control
	// Direct2D: repeat, reflect, pad; no individual control
	// Core Graphics: none, pad; before and after individually
	// TODO cairo documentation is inconsistent about pad

	// TODO images

	// TODO transforms
};

struct uiDrawBrushGradientStop {
	double Pos;
	double R;
	double G;
	double B;
	double A;
};

struct uiDrawStrokeParams {
	uiDrawLineCap Cap;
	uiDrawLineJoin Join;
	// TODO what if this is 0? on windows there will be a crash with dashing
	double Thickness;
	double MiterLimit;
	double *Dashes;
	// TOOD what if this is 1 on Direct2D?
	// TODO what if a dash is 0 on Cairo or Quartz?
	size_t NumDashes;
	double DashPhase;
};

_UI_EXTERN uiDrawPath *uiDrawNewPath(uiDrawFillMode fillMode);
_UI_EXTERN void uiDrawFreePath(uiDrawPath *p);

_UI_EXTERN void uiDrawPathNewFigure(uiDrawPath *p, double x, double y);
_UI_EXTERN void uiDrawPathNewFigureWithArc(uiDrawPath *p, double xCenter, double yCenter, double radius, double startAngle, double sweep, int negative);
_UI_EXTERN void uiDrawPathLineTo(uiDrawPath *p, double x, double y);
// notes: angles are both relative to 0 and go counterclockwise
// TODO is the initial line segment on cairo and OS X a proper join?
// TODO what if sweep < 0?
_UI_EXTERN void uiDrawPathArcTo(uiDrawPath *p, double xCenter, double yCenter, double radius, double startAngle, double sweep, int negative);
_UI_EXTERN void uiDrawPathBezierTo(uiDrawPath *p, double c1x, double c1y, double c2x, double c2y, double endX, double endY);
// TODO quadratic bezier
_UI_EXTERN void uiDrawPathCloseFigure(uiDrawPath *p);

// TODO effect of these when a figure is already started
_UI_EXTERN void uiDrawPathAddRectangle(uiDrawPath *p, double x, double y, double width, double height);

_UI_EXTERN void uiDrawPathEnd(uiDrawPath *p);

_UI_EXTERN void uiDrawStroke(uiDrawContext *c, uiDrawPath *path, uiDrawBrush *b, uiDrawStrokeParams *p);
_UI_EXTERN void uiDrawFill(uiDrawContext *c, uiDrawPath *path, uiDrawBrush *b);

// TODO primitives:
// - rounded rectangles
// - elliptical arcs
// - quadratic bezier curves

_UI_EXTERN void uiDrawMatrixSetIdentity(uiDrawMatrix *m);
_UI_EXTERN void uiDrawMatrixTranslate(uiDrawMatrix *m, double x, double y);
_UI_EXTERN void uiDrawMatrixScale(uiDrawMatrix *m, double xCenter, double yCenter, double x, double y);
_UI_EXTERN void uiDrawMatrixRotate(uiDrawMatrix *m, double x, double y, double amount);
_UI_EXTERN void uiDrawMatrixSkew(uiDrawMatrix *m, double x, double y, double xamount, double yamount);
_UI_EXTERN void uiDrawMatrixMultiply(uiDrawMatrix *dest, uiDrawMatrix *src);
_UI_EXTERN int uiDrawMatrixInvertible(uiDrawMatrix *m);
_UI_EXTERN int uiDrawMatrixInvert(uiDrawMatrix *m);
_UI_EXTERN void uiDrawMatrixTransformPoint(uiDrawMatrix *m, double *x, double *y);
_UI_EXTERN void uiDrawMatrixTransformSize(uiDrawMatrix *m, double *x, double *y);

_UI_EXTERN void uiDrawTransform(uiDrawContext *c, uiDrawMatrix *m);

// TODO add a uiDrawPathStrokeToFill() or something like that
_UI_EXTERN void uiDrawClip(uiDrawContext *c, uiDrawPath *path);

_UI_EXTERN void uiDrawSave(uiDrawContext *c);
_UI_EXTERN void uiDrawRestore(uiDrawContext *c);

// TODO manage the use of Text, Font, and TextFont, and of the uiDrawText prefix in general

///// TODO
typedef struct uiDrawFontFamilies uiDrawFontFamilies;

_UI_EXTERN uiDrawFontFamilies *uiDrawListFontFamilies(void);
_UI_EXTERN uintmax_t uiDrawFontFamiliesNumFamilies(uiDrawFontFamilies *ff);
_UI_EXTERN char *uiDrawFontFamiliesFamily(uiDrawFontFamilies *ff, uintmax_t n);
_UI_EXTERN void uiDrawFreeFontFamilies(uiDrawFontFamilies *ff);
///// END TODO

typedef struct uiDrawTextLayout uiDrawTextLayout;
typedef struct uiDrawTextFont uiDrawTextFont;
typedef struct uiDrawTextFontDescriptor uiDrawTextFontDescriptor;
typedef struct uiDrawTextFontMetrics uiDrawTextFontMetrics;

_UI_ENUM(uiDrawTextWeight) {
	uiDrawTextWeightThin,
	uiDrawTextWeightUltraLight,
	uiDrawTextWeightLight,
	uiDrawTextWeightBook,
	uiDrawTextWeightNormal,
	uiDrawTextWeightMedium,
	uiDrawTextWeightSemiBold,
	uiDrawTextWeightBold,
	uiDrawTextWeightUtraBold,
	uiDrawTextWeightHeavy,
	uiDrawTextWeightUltraHeavy,
};

_UI_ENUM(uiDrawTextItalic) {
	uiDrawTextItalicNormal,
	uiDrawTextItalicOblique,
	uiDrawTextItalicItalic,
};

_UI_ENUM(uiDrawTextStretch) {
	uiDrawTextStretchUltraCondensed,
	uiDrawTextStretchExtraCondensed,
	uiDrawTextStretchCondensed,
	uiDrawTextStretchSemiCondensed,
	uiDrawTextStretchNormal,
	uiDrawTextStretchSemiExpanded,
	uiDrawTextStretchExpanded,
	uiDrawTextStretchExtraExpanded,
	uiDrawTextStretchUltraExpanded,
};

struct uiDrawTextFontDescriptor {
	const char *Family;
	double Size;
	uiDrawTextWeight Weight;
	uiDrawTextItalic Italic;
	uiDrawTextStretch Stretch;
};

struct uiDrawTextFontMetrics {
	double Ascent;
	double Descent;
	double Leading;
	// TODO do these two mean the same across all platforms?
	double UnderlinePos;
	double UnderlineThickness;
};

_UI_EXTERN uiDrawTextFont *uiDrawLoadClosestFont(const uiDrawTextFontDescriptor *desc);
_UI_EXTERN void uiDrawFreeTextFont(uiDrawTextFont *font);
_UI_EXTERN uintptr_t uiDrawTextFontHandle(uiDrawTextFont *font);
_UI_EXTERN void uiDrawTextFontDescribe(uiDrawTextFont *font, uiDrawTextFontDescriptor *desc);
// TODO make copy with given attributes methods?
// TODO yuck this name
_UI_EXTERN void uiDrawTextFontGetMetrics(uiDrawTextFont *font, uiDrawTextFontMetrics *metrics);

// TODO initial line spacing? and what about leading?
_UI_EXTERN uiDrawTextLayout *uiDrawNewTextLayout(const char *text, uiDrawTextFont *defaultFont, double width);
_UI_EXTERN void uiDrawFreeTextLayout(uiDrawTextLayout *layout);
// TODO get width
_UI_EXTERN void uiDrawTextLayoutSetWidth(uiDrawTextLayout *layout, double width);
_UI_EXTERN void uiDrawTextLayoutExtents(uiDrawTextLayout *layout, double *width, double *height);

// and the attributes that you can set on a text layout
_UI_EXTERN void uiDrawTextLayoutSetColor(uiDrawTextLayout *layout, intmax_t startChar, intmax_t endChar, double r, double g, double b, double a);

_UI_EXTERN void uiDrawText(uiDrawContext *c, double x, double y, uiDrawTextLayout *layout);

_UI_ENUM(uiModifiers) {
	uiModifierCtrl = 1 << 0,
	uiModifierAlt = 1 << 1,
	uiModifierShift = 1 << 2,
	uiModifierSuper = 1 << 3,
};

// TODO document drag captures
struct uiAreaMouseEvent {
	// TODO document what these mean for scrolling areas
	double X;
	double Y;

	// TODO see draw above
	double AreaWidth;
	double AreaHeight;

	uintmax_t Down;
	uintmax_t Up;

	uintmax_t Count;

	uiModifiers Modifiers;

	uint64_t Held1To64;
};

_UI_ENUM(uiExtKey) {
	uiExtKeyEscape = 1,
	uiExtKeyInsert,			// equivalent to "Help" on Apple keyboards
	uiExtKeyDelete,
	uiExtKeyHome,
	uiExtKeyEnd,
	uiExtKeyPageUp,
	uiExtKeyPageDown,
	uiExtKeyUp,
	uiExtKeyDown,
	uiExtKeyLeft,
	uiExtKeyRight,
	uiExtKeyF1,			// F1..F12 are guaranteed to be consecutive
	uiExtKeyF2,
	uiExtKeyF3,
	uiExtKeyF4,
	uiExtKeyF5,
	uiExtKeyF6,
	uiExtKeyF7,
	uiExtKeyF8,
	uiExtKeyF9,
	uiExtKeyF10,
	uiExtKeyF11,
	uiExtKeyF12,
	uiExtKeyN0,			// numpad keys; independent of Num Lock state
	uiExtKeyN1,			// N0..N9 are guaranteed to be consecutive
	uiExtKeyN2,
	uiExtKeyN3,
	uiExtKeyN4,
	uiExtKeyN5,
	uiExtKeyN6,
	uiExtKeyN7,
	uiExtKeyN8,
	uiExtKeyN9,
	uiExtKeyNDot,
	uiExtKeyNEnter,
	uiExtKeyNAdd,
	uiExtKeyNSubtract,
	uiExtKeyNMultiply,
	uiExtKeyNDivide,
};

struct uiAreaKeyEvent {
	char Key;
	uiExtKey ExtKey;
	uiModifiers Modifier;

	uiModifiers Modifiers;

	int Up;
};

typedef struct uiFontButton uiFontButton;
#define uiFontButton(this) ((uiFontButton *) (this))
// TODO document this returns a new font
_UI_EXTERN uiDrawTextFont *uiFontButtonFont(uiFontButton *b);
// TOOD SetFont, mechanics
_UI_EXTERN void uiFontButtonOnChanged(uiFontButton *b, void (*f)(uiFontButton *, void *), void *data);
_UI_EXTERN uiFontButton *uiNewFontButton(void);

typedef struct uiColorButton uiColorButton;
#define uiColorButton(this) ((uiColorButton *) (this))
_UI_EXTERN void uiColorButtonColor(uiColorButton *b, double *r, double *g, double *bl, double *a);
_UI_EXTERN void uiColorButtonSetColor(uiColorButton *b, double r, double g, double bl, double a);
_UI_EXTERN void uiColorButtonOnChanged(uiColorButton *b, void (*f)(uiColorButton *, void *), void *data);
_UI_EXTERN uiColorButton *uiNewColorButton(void);

#ifdef __cplusplus
}
#endif

#endif