include/rive/factory.hpp

/*
 * Copyright 2022 Rive
 */

#ifndef _RIVE_FACTORY_HPP_
#define _RIVE_FACTORY_HPP_

#include "rive/renderer.hpp"
#include "rive/text_engine.hpp"
#include "rive/audio/audio_source.hpp"
#include "rive/refcnt.hpp"
#include "rive/span.hpp"
#include "rive/math/aabb.hpp"

#include <stdio.h>
#include <cstdint>
#include <vector>

namespace rive
{

class RawPath;
namespace ore
{
class Context;
}
namespace cmd
{
class DeferredCanvasHost;
}

class Factory
{
public:
  Factory() {}
  virtual ~Factory() {}

  virtual rcp<RenderBuffer> makeRenderBuffer(
      RenderBufferType,
      RenderBufferFlags,
      size_t sizeInBytes) = 0;

  virtual rcp<ImageMeshInstances> makeImageMeshInstances(size_t count)
  {
    return make_rcp<ImageMeshInstances>(count);
  }

  virtual rcp<RenderShader> makeLinearGradient(
      float sx,
      float sy,
      float ex,
      float ey,
      const ColorInt colors[], // [count]
      const float stops[],     // [count]
      size_t count) = 0;

  virtual rcp<RenderShader> makeRadialGradient(
      float cx,
      float cy,
      float radius,
      const ColorInt colors[], // [count]
      const float stops[],     // [count]
      size_t count) = 0;

  virtual rcp<RenderShader> makeAngularGradient(
      const ColorInt colors[], // [count]
      const float stops[],     // [count]
      size_t count)
  {
    // TODO: This is defaulted to make a linear gradient with a single stop
    // (i.e. it's solid color) for platforms where angular gradients are not
    // yet implemented, mostly to have it do *something*. This defaulting
    // should get removed once there's an implementation everywhere (which
    // may still be doing something like this if, as with the SVG renderer,
    // this isn't possible to implement properly).
    return makeLinearGradient(
        0.0f,
        0.0f,
        1.0f,
        0.0f,
        colors,
        stops,
        std::min(size_t(1), count));
  }

  // Returns a full-formed RenderPath -- can be treated as immutable
  // This call might swap out the arrays backing the points and verbs in the
  // given RawPath, so the caller can expect it to be in an undefined state
  // upon return.
  virtual rcp<RenderPath> makeRenderPath(RawPath&, FillRule) = 0;

  // Deprecated -- working to make RenderPath's immutable
  virtual rcp<RenderPath> makeEmptyRenderPath() = 0;

  virtual rcp<RenderPaint> makeRenderPaint() = 0;

  virtual rcp<RenderImage> decodeImage(Span<const uint8_t>) = 0;

  // GPU ore context, when this factory is backed by a RenderContext.
  // Null for non-GPU factories. Kept last in the virtual section to avoid
  // shifting existing vtable slots.
  virtual ore::Context* ore() { return nullptr; }

  // The GPU render context an import through this factory should give its
  // scripts, as a Factory so this header stays free of gpu types. A render
  // context answers with itself; a recording session answers with the one it
  // records for, which on web is null until a render texture attaches, so
  // callers that deferred an allocation ask again rather than caching the
  // null they saw at import. Null means the importer cannot route GPU
  // scripting.
  virtual Factory* renderContext() { return nullptr; }

  // Set when script canvas work must record rather than issue. Null means
  // scripts draw straight to the driver.
  virtual cmd::DeferredCanvasHost* deferredCanvasHost() { return nullptr; }

  // A host that can hand out an offscreen frame to draw into, used by
  // features that rasterize into a texture rather than to the screen (e.g.
  // an artboard caching itself as a bitmap). A recording session doubles as
  // one, which is the default.
  //
  // Kept separate from deferredCanvasHost() on purpose: that one answers
  // "content is being recorded for a later replay", and the scripting layer
  // keys canvas allocation and frame handling off it. A renderer that draws
  // immediately can serve this hook, but must not answer that one.
  virtual cmd::DeferredCanvasHost* canvasContentHost()
  {
    return deferredCanvasHost();
  }

  // Whether THIS device can apply a layer mask. Distinct from the hook of the
  // same name on DeferredCanvasHost, which is the one a caller about to
  // rasterize asks: that one is about the canvas being handed out, this one
  // is about the device, and the two are different objects whenever a factory
  // delegates its host elsewhere.
  //
  // It exists for exactly one caller. A recording session has to ask the
  // context it will replay against, and all it holds is a Factory* -- which
  // in a Canvas-2D build is not a render context at all, so it must dispatch
  // rather than cast.
  //
  // No by default, matching the host hook and for the same reason: the
  // default Renderer::applyLayerMask is itself a no-op, so a factory that has
  // not answered is one whose renderer will drop the op -- and a yes here
  // reaches a session, which reports support, which has the caller crop to
  // the mask box on the way to dropping it. That is exactly the Canvas-2D
  // case: its factory is not a render context and its renderer cannot apply
  // the op. RenderContext and SerializingFactory opt in.
  virtual bool supportsLayerMask() const { return false; }

  rcp<Font> decodeFont(Span<const uint8_t>);
  rcp<Font> decodeFont(std::vector<uint8_t>&&);

  rcp<AudioSource> decodeAudio(Span<const uint8_t>);

  // Non-virtual helpers

  rcp<RenderPath> makeRenderPath(const AABB&);
};

} // namespace rive
#endif