SlideShowView.c

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/*
 * ObjectivelyMVC: Object oriented MVC framework for SDL3 and C.
 * Copyright (C) 2014 Jay Dolan <jay@jaydolan.com>
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 *
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 *
 * 3. This notice may not be removed or altered from any source distribution.
 */
 
#include <assert.h>
 
#include <SDL3/SDL_timer.h>
 
#include "SlideShowView.h"
 
#define _Class _SlideShowView
 
#pragma mark - Object
 
static void dealloc(Object *self) {
 
  SlideShowView *this = (SlideShowView *) self;
 
  release(this->images);
 
  super(Object, self, dealloc);
}
 
#pragma mark - View
 
static View *init(View *self) {
  return (View *) $((SlideShowView *) self, initWithFrame, NULL);
}
 
static void render(View *self, Renderer *renderer) {
 
  super(View, self, render, renderer);
 
  SlideShowView *this = (SlideShowView *) self;
 
  const Array *images = (Array *) this->images;
  if (images->count == 0) {
    return;
  }
 
  const Uint64 now = SDL_GetTicks();
 
  if (this->current->image == NULL) {
    Image *first = $(images, firstObject);
    $(this->current, setImage, first);
    this->fadeEndedAt = now;
    return;
  }
 
  if (images->count < 2) {
    return;
  }
 
  if (this->fadeStartedAt) {
    const float frac = (float) (now - this->fadeStartedAt) / (float) this->fadeDuration;
    this->next->color.a = (Uint8) (SDL_min(frac, 1.f) * 255.f);
    if (frac >= 1.f) {
      $(this->current, setImage, this->next->image);
      $(this->next, setImage, NULL);
      this->next->color.a = 0;
      this->fadeStartedAt = 0;
      this->fadeEndedAt = now;
    }
  } else if (now - this->fadeEndedAt >= this->slideDuration) {
    this->index = (this->index + 1) % images->count;
    Image *image = $(images, objectAtIndex, this->index);
    $(this->next, setImage, image);
    this->fadeStartedAt = now;
  }
}
 
#pragma mark - SlideShowView
 
static void addImage(SlideShowView *self, Image *image) {
 
  assert(image);
 
  $(self->images, addObject, image);
}
 
static SlideShowView *initWithFrame(SlideShowView *self, const SDL_Rect *frame) {
 
  self = (SlideShowView *) super(View, self, initWithFrame, frame);
  if (self) {
    self->images = $(alloc(Array), init);
    assert(self->images);
 
    self->slideDuration = 5000;
    self->fadeDuration = 1000;
 
    self->current = $(alloc(ImageView), initWithFrame, NULL);
    assert(self->current);
    $((View *) self, addSubview, (View *) self->current);
    release(self->current);
 
    self->next = $(alloc(ImageView), initWithFrame, NULL);
    assert(self->next);
    self->next->color.a = 0;
    $((View *) self, addSubview, (View *) self->next);
    release(self->next);
  }
 
  return self;
}
 
#pragma mark - Class lifecycle
 
static void initialize(Class *clazz) {
 
  ((ObjectInterface *) clazz->interface)->dealloc = dealloc;
 
  ((ViewInterface *) clazz->interface)->render = render;
  ((ViewInterface *) clazz->interface)->init = init;
 
  ((SlideShowViewInterface *) clazz->interface)->addImage = addImage;
  ((SlideShowViewInterface *) clazz->interface)->initWithFrame = initWithFrame;
}
 
Class *_SlideShowView(void) {
  static Class *clazz;
  static Once once;
 
  do_once(&once, {
    clazz = _initialize(&(const ClassDef) {
      .name = "SlideShowView",
      .superclass = _View(),
      .instanceSize = sizeof(SlideShowView),
      .interfaceOffset = offsetof(SlideShowView, interface),
      .interfaceSize = sizeof(SlideShowViewInterface),
      .initialize = initialize,
    });
  });
 
  return clazz;
}
 
#undef _Class