ScrollBar.c File Reference

#include <assert.h>
#include "ScrollBar.h"
#include "ScrollView.h"

Go to the source code of this file.

Macros
#define	_Class   _ScrollBar

Functions
Class *	_ScrollBar (void)
static void	dealloc (Object *self)
static void	didDragHandle (ScrollHandle *handle, float delta)
	ScrollHandleDelegate; maps handle travel onto the ScrollView's content offset.
static View *	init (View *self)
static void	initialize (Class *clazz)
static ScrollBar *	initWithScrollView (ScrollBar *self, ScrollView *scrollView)
static void	layoutSubviews (View *self)
static void	respondToEvent (View *self, const SDL_Event *event)
static void	setScrollView (ScrollBar *self, ScrollView *scrollView)

Variables
const EnumName	ScrollBarVisibilityNames []

Macro Definition Documentation

_Class

#define _Class   _ScrollBar

Definition at line 29 of file ScrollBar.c.

Function Documentation

_ScrollBar()

Class * _ScrollBar

(

void

)

Definition at line 225 of file ScrollBar.c.

                        {
  static Class *clazz;
  static Once once;
 
  do_once(&once, {
    clazz = _initialize(&(const ClassDef) {
      .name = "ScrollBar",
      .superclass = _View(),
      .instanceSize = sizeof(ScrollBar),
      .interfaceOffset = offsetof(ScrollBar, interface),
      .interfaceSize = sizeof(ScrollBarInterface),
      .initialize = initialize,
    });
  });
 
  return clazz;
}

dealloc()

static void dealloc ( Object *  self )

static

See also

Object::dealloc(Object *)

Definition at line 71 of file ScrollBar.c.

                                  {
 
  ScrollBar *this = (ScrollBar *) self;
 
  release(this->handle);
 
  super(Object, self, dealloc);
}

didDragHandle()

static void didDragHandle ( ScrollHandle *  handle, float  delta  )

static

ScrollHandleDelegate; maps handle travel onto the ScrollView's content offset.

Definition at line 42 of file ScrollBar.c.

                                                             {
 
  ScrollBar *self = handle->delegate.self;
 
  if (self->scrollView) {
 
    const SDL_Rect track = $((View *) self, bounds);
    const SDL_Size content = $((View *) self->scrollView->contentView, size);
    const SDL_Rect visible = $((View *) self->scrollView, bounds);
 
    const int scrollRange = content.h - visible.h;
    const int travel = track.h - ((View *) self->handle)->frame.h;
 
    if (scrollRange > 0 && travel > 0) {
 
      SDL_Point offset = self->scrollView->contentOffset;
      offset.y -= (int) (delta * ((float) scrollRange / travel));
 
      $(self->scrollView, scrollToOffset, &offset);
      ((View *) self)->needsLayout = true;
    }
  }
}

init()

static View * init ( View *  self )

static

See also

View::init(View *)

Definition at line 85 of file ScrollBar.c.

                              {
  return (View *) $((ScrollBar *) self, initWithScrollView, NULL);
}

initialize()

static void initialize ( Class *  clazz )

static

See also

Class::initialize(Class *)

Definition at line 209 of file ScrollBar.c.

                                     {
 
  ((ObjectInterface *) clazz->interface)->dealloc = dealloc;
 
  ((ViewInterface *) clazz->interface)->init = init;
  ((ViewInterface *) clazz->interface)->layoutSubviews = layoutSubviews;
  ((ViewInterface *) clazz->interface)->respondToEvent = respondToEvent;
 
  ((ScrollBarInterface *) clazz->interface)->initWithScrollView = initWithScrollView;
  ((ScrollBarInterface *) clazz->interface)->setScrollView = setScrollView;
}

initWithScrollView()

static ScrollBar * initWithScrollView ( ScrollBar *  self, ScrollView *  scrollView  )

static

Definition at line 173 of file ScrollBar.c.

                                                                              {
 
  self = (ScrollBar *) super(View, self, initWithFrame, NULL);
  if (self) {
 
    $((View *) self, addClassName, "scrollBar");
    ((View *) self)->clipsSubviews = true;
 
    self->handle = $(alloc(ScrollHandle), initWithFrame, NULL);
    assert(self->handle);
    self->handle->delegate.self = self;
    self->handle->delegate.didDrag = didDragHandle;
    $((View *) self, addSubview, (View *) self->handle);
 
    $(self, setScrollView, scrollView);
  }
 
  return self;
}

layoutSubviews()

static void layoutSubviews ( View *  self )

static

See also

View::layoutSubviews(View *)

Definition at line 92 of file ScrollBar.c.

                                       {
 
  ScrollBar *this = (ScrollBar *) self;
 
  super(View, self, layoutSubviews);
 
  if (this->scrollView == NULL || this->scrollView->contentView == NULL) {
    return;
  }
 
  const SDL_Rect track = $(self, bounds);
  const SDL_Size content = $(this->scrollView->contentView, size);
  const SDL_Rect visible = $((View *) this->scrollView, bounds);
 
  View *handle = (View *) this->handle;
 
  if (content.h <= visible.h || track.h <= 0) {
    handle->frame = (SDL_Rect) { 0, 0, track.w, track.h };
  } else {
 
    const int scrollRange = content.h - visible.h;
 
    int handleH = (int) ((float) track.h * visible.h / content.h);
    handleH = clamp(handleH, handle->minSize.h, track.h);
 
    const int travel = track.h - handleH;
    const float fraction = clamp((float) (-this->scrollView->contentOffset.y) / scrollRange, 0.f, 1.f);
 
    handle->frame = (SDL_Rect) { 0, (int) (fraction * travel), track.w, handleH };
  }
}

respondToEvent()

static void respondToEvent ( View *  self, const SDL_Event *  event  )

static

See also

View::respondToEvent(View *, const SDL_Event *)

Definition at line 127 of file ScrollBar.c.

                                                               {
 
  ScrollBar *this = (ScrollBar *) self;
 
  switch (event->type) {
 
    case SDL_EVENT_MOUSE_BUTTON_DOWN:
      if (this->scrollView) {
 
        const SDL_Point point = MakePoint(event->button.x, event->button.y);
        const SDL_Rect handleFrame = $((View *) this->handle, renderFrame);
        const SDL_Rect visible = $((View *) this->scrollView, bounds);
 
        SDL_Point offset = this->scrollView->contentOffset;
 
        if (point.y < handleFrame.y) {
          offset.y += visible.h;
        } else if (point.y > handleFrame.y + handleFrame.h) {
          offset.y -= visible.h;
        }
 
        $(this->scrollView, scrollToOffset, &offset);
        self->needsLayout = true;
      }
      return;
 
    case SDL_EVENT_MOUSE_BUTTON_UP:
      $(self, resignTouchResponder);
      return;
 
    case SDL_EVENT_MOUSE_MOTION:
      return;
 
    default:
      break;
  }
 
  super(View, self, respondToEvent, event);
}

setScrollView()

static void setScrollView ( ScrollBar *  self, ScrollView *  scrollView  )

static

Definition at line 197 of file ScrollBar.c.

                                                                   {
 
  self->scrollView = scrollView;
 
  ((View *) self)->needsLayout = true;
}

Variable Documentation

ScrollBarVisibilityNames

const EnumName ScrollBarVisibilityNames[]

Initial value:

= MakeEnumNames(
  MakeEnumAlias(ScrollBarShow, show),
  MakeEnumAlias(ScrollBarHide, hide),
  MakeEnumAlias(ScrollBarAuto, auto)
)

Definition at line 31 of file ScrollBar.c.