text: /*
   * This an unstable interface of wlroots. No guarantees are made regarding the
   * future consistency of this API.
   */
  #ifndef WLR_USE_UNSTABLE
  #error "Add -DWLR_USE_UNSTABLE to enable unstable wlroots features"
  #endif
  
  #ifndef WLR_RENDER_WLR_RENDERER_H
  #define WLR_RENDER_WLR_RENDERER_H
  
  #include <stdint.h>
  #include <wayland-server-core.h>
  #include <wlr/backend.h>
  #include <wlr/render/wlr_texture.h>
  #include <wlr/types/wlr_box.h>
  
  enum wlr_renderer_read_pixels_flags {
  	WLR_RENDERER_READ_PIXELS_Y_INVERT = 1,
  };
  
  struct wlr_renderer_impl;
  struct wlr_drm_format_set;
  struct wlr_buffer;
  
  struct wlr_renderer {
  	const struct wlr_renderer_impl *impl;
  
  	bool rendering;
  
  	struct {
  		struct wl_signal destroy;
  	} events;
  };
  
  struct wlr_renderer *wlr_renderer_autocreate(struct wlr_backend *backend);
  
  void wlr_renderer_begin(struct wlr_renderer *r, uint32_t width, uint32_t height);
  void wlr_renderer_end(struct wlr_renderer *r);
  void wlr_renderer_clear(struct wlr_renderer *r, const float color[static 4]);
  /**
   * Defines a scissor box. Only pixels that lie within the scissor box can be
   * modified by drawing functions. Providing a NULL `box` disables the scissor
   * box.
   */
  void wlr_renderer_scissor(struct wlr_renderer *r, struct wlr_box *box);
  /**
   * Renders the requested texture.
   */
  bool wlr_render_texture(struct wlr_renderer *r, struct wlr_texture *texture,
  	const float projection[static 9], int x, int y, float alpha);
  /**
   * Renders the requested texture using the provided matrix.
   */
  bool wlr_render_texture_with_matrix(struct wlr_renderer *r,
  	struct wlr_texture *texture, const float matrix[static 9], float alpha);
  /**
   * Renders the requested texture using the provided matrix, after cropping it
   * to the provided rectangle.
   */
  bool wlr_render_subtexture_with_matrix(struct wlr_renderer *r,
  	struct wlr_texture *texture, const struct wlr_fbox *box,
  	const float matrix[static 9], float alpha);
  /**
   * Renders a solid rectangle in the specified color.
   */
  void wlr_render_rect(struct wlr_renderer *r, const struct wlr_box *box,
  	const float color[static 4], const float projection[static 9]);
  /**
   * Renders a solid quadrangle in the specified color with the specified matrix.
   */
  void wlr_render_quad_with_matrix(struct wlr_renderer *r,
  	const float color[static 4], const float matrix[static 9]);
  /**
   * Renders a solid ellipse in the specified color.
   */
  void wlr_render_ellipse(struct wlr_renderer *r, const struct wlr_box *box,
  	const float color[static 4], const float projection[static 9]);
  /**
   * Renders a solid ellipse in the specified color with the specified matrix.
   */
  void wlr_render_ellipse_with_matrix(struct wlr_renderer *r,
  	const float color[static 4], const float matrix[static 9]);
  /**
   * Get the shared-memory formats supporting import usage. Buffers allocated
   * with a format from this list may be imported via wlr_texture_from_pixels.
   */
  const uint32_t *wlr_renderer_get_shm_texture_formats(
  	struct wlr_renderer *r, size_t *len);
  /**
   * Returns true if this wl_buffer is a wl_drm buffer.
   */
  bool wlr_renderer_resource_is_wl_drm_buffer(struct wlr_renderer *renderer,
  	struct wl_resource *buffer);
  /**
   * Gets the width and height of a wl_drm buffer.
   */
  void wlr_renderer_wl_drm_buffer_get_size(struct wlr_renderer *renderer,
  	struct wl_resource *buffer, int *width, int *height);
  /**
   * Get the DMA-BUF formats supporting sampling usage. Buffers allocated with
   * a format from this list may be imported via wlr_texture_from_dmabuf.
   */
  const struct wlr_drm_format_set *wlr_renderer_get_dmabuf_texture_formats(
  	struct wlr_renderer *renderer);
  /**
   * Reads out of pixels of the currently bound surface into data. `stride` is in
   * bytes.
   *
   * If `flags` is not NULl, the caller indicates that it accepts frame flags
   * defined in `enum wlr_renderer_read_pixels_flags`.
   */
  bool wlr_renderer_read_pixels(struct wlr_renderer *r, uint32_t fmt,
  	uint32_t *flags, uint32_t stride, uint32_t width, uint32_t height,
  	uint32_t src_x, uint32_t src_y, uint32_t dst_x, uint32_t dst_y, void *data);
  
  /**
   * Blits the dmabuf in src onto the one in dst.
   */
  bool wlr_renderer_blit_dmabuf(struct wlr_renderer *r,
  	struct wlr_dmabuf_attributes *dst, struct wlr_dmabuf_attributes *src);
  /**
   * Creates necessary shm and invokes the initialization of the implementation.
   *
   * Returns false on failure.
   */
  bool wlr_renderer_init_wl_display(struct wlr_renderer *r,
  	struct wl_display *wl_display);
  
  /**
   * Obtains the FD of the DRM device used for rendering, or -1 if unavailable.
   *
   * The caller doesn't have ownership of the FD, it must not close it.
   */
  int wlr_renderer_get_drm_fd(struct wlr_renderer *r);
  
  /**
   * Destroys this wlr_renderer. Textures must be destroyed separately.
   */
  void wlr_renderer_destroy(struct wlr_renderer *renderer);
  
  /**
   * Gets underlying wlr_elg if defined.
   */
  struct wlr_egl *wlr_renderer_get_egl(struct wlr_renderer *renderer);
  
  /**
   * Gets the parameters of wayland buffer.
   */
  bool wlr_renderer_wl_buffer_get_params(struct wlr_renderer *renderer,
  	struct wl_resource *buffer, int *width, int *height, int *inverted_y);
  #endif
  