text: /* Copyright 2020 Jaakko Keränen <jaakko.keranen@iki.fi>
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:
  
  1. Redistributions of source code must retain the above copyright notice, this
     list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright notice,
     this list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
  
  #include "scrollwidget.h"
  #include "paint.h"
  #include "util.h"
  
  iDefineObjectConstruction(ScrollWidget)
  
  struct Impl_ScrollWidget {
      iWidget widget;
      iRangei range;
      int thumb;
      int thumbSize;
      iClick click;
      int startThumb;
  };
  
  void init_ScrollWidget(iScrollWidget *d) {
      iWidget *w = as_Widget(d);
      init_Widget(w);
      setId_Widget(w, "scroll");
      setFlags_Widget(w,
                      fixedWidth_WidgetFlag | resizeToParentHeight_WidgetFlag |
                          moveToParentRightEdge_WidgetFlag | touchDrag_WidgetFlag,
                      iTrue);
      w->rect.size.x = gap_UI * 3;
      init_Click(&d->click, d, SDL_BUTTON_LEFT);
  }
  
  void deinit_ScrollWidget(iScrollWidget *d) {
      iUnused(d);
  }
  
  static int thumbSize_ScrollWidget_(const iScrollWidget *d) {
      return iMax(gap_UI * 6, d->thumbSize);
  }
  
  static iRect thumbRect_ScrollWidget_(const iScrollWidget *d) {
      const iRect bounds = bounds_Widget(constAs_Widget(d));
      iRect rect = init_Rect(bounds.pos.x, bounds.pos.y, bounds.size.x, 0);
      const int total = size_Range(&d->range);
      if (total > 0) {
          const int tsize = thumbSize_ScrollWidget_(d);
  //        iAssert(tsize <= height_Rect(bounds));
          const int tpos =
              iClamp((float) d->thumb / (float) total, 0, 1) * (height_Rect(bounds) - tsize);
          rect.pos.y  = bounds.pos.y + tpos;
          rect.size.y = tsize;
      }
      return rect;
  }
  
  static void checkVisible_ScrollWidget_(iScrollWidget *d) {
      setFlags_Widget(as_Widget(d), hidden_WidgetFlag, height_Rect(thumbRect_ScrollWidget_(d)) == 0);
  }
  
  void setRange_ScrollWidget(iScrollWidget *d, iRangei range) {
      range.end = iMax(range.start, range.end);
      d->range  = range;
      checkVisible_ScrollWidget_(d);
  }
  
  void setThumb_ScrollWidget(iScrollWidget *d, int thumb, int thumbSize) {
      d->thumb     = thumb;
      d->thumbSize = thumbSize;
      checkVisible_ScrollWidget_(d);
  }
  
  static iBool processEvent_ScrollWidget_(iScrollWidget *d, const SDL_Event *ev) {
      iWidget *w = as_Widget(d);
      switch (processEvent_Click(&d->click, ev)) {
          case started_ClickResult:
              setFlags_Widget(w, pressed_WidgetFlag, iTrue);
              d->startThumb = d->thumb;
              refresh_Widget(w);
              return iTrue;
          case drag_ClickResult: {
              const iRect bounds = bounds_Widget(w);
              const int offset = delta_Click(&d->click).y;
              const int total = size_Range(&d->range);
              int dpos = (float) offset / (float) (height_Rect(bounds) - thumbSize_ScrollWidget_(d)) * total;
              d->thumb = iClamp(d->startThumb + dpos, d->range.start, d->range.end);
              postCommand_Widget(w, "scroll.moved arg:%d", d->thumb);
              refresh_Widget(w);
              return iTrue;
          }
          case finished_ClickResult:
          case aborted_ClickResult:
              if (!isMoved_Click(&d->click)) {
                  /* Page up/down. */
                  const iRect tr = thumbRect_ScrollWidget_(d);
                  const int y = pos_Click(&d->click).y;
                  int pgDir = 0;
                  if (y < top_Rect(tr)) {
                      pgDir = -1;
                  }
                  else if (y > bottom_Rect(tr)) {
                      pgDir = +1;
                  }
                  if (pgDir) {
                      postCommand_Widget(w, "scroll.page arg:%d", pgDir);
                  }
              }
              setFlags_Widget(w, pressed_WidgetFlag, iFalse);
              refresh_Widget(w);
              return iTrue;
          default:
              break;
      }
      return processEvent_Widget(w, ev);
  }
  
  static void draw_ScrollWidget_(const iScrollWidget *d) {
      const iWidget *w         = constAs_Widget(d);
      const iRect    bounds    = bounds_Widget(w);
      const iBool    isPressed = (flags_Widget(w) & pressed_WidgetFlag) != 0;
      if (bounds.size.x > 0) {
          iPaint p;
          init_Paint(&p);
          //drawVLine_Paint(&p, topLeft_Rect(bounds), height_Rect(bounds), uiSeparator_ColorId);
          const iRect thumbRect = shrunk_Rect(
              thumbRect_ScrollWidget_(d), init_I2(isPressed ? gap_UI : (gap_UI * 4 / 3), gap_UI / 2));
          fillRect_Paint(&p, thumbRect, isPressed ? uiBackgroundPressed_ColorId : tmQuote_ColorId);
      }
  }
  
  iBeginDefineSubclass(ScrollWidget, Widget)
      .processEvent = (iAny *) processEvent_ScrollWidget_,
      .draw         = (iAny *) draw_ScrollWidget_,
  iEndDefineSubclass(ScrollWidget)
  