vbe.c

grub 1.95 linux 的bootloader 源代码

  if (y < 0)
    {
      height += y;
      offset_y -= y;
      y = 0;
    }

  /* Do not allow drawing out of viewport.  */
  if ((x + width) > render_target->viewport.width)
    width = render_target->viewport.width - x;
  if ((y + height) > render_target->viewport.height)
    height = render_target->viewport.height - y;

  if ((offset_x + width) > bitmap->mode_info.width)
    width = bitmap->mode_info.width - offset_x;
  if ((offset_y + height) > bitmap->mode_info.height)
    height = bitmap->mode_info.height - offset_y;

  /* Limit drawing to source render target dimensions.  */
  if (width > bitmap->mode_info.width)
    width = bitmap->mode_info.width;

  if (height > bitmap->mode_info.height)
    height = bitmap->mode_info.height;

  /* Add viewport offset.  */
  x += render_target->viewport.x;
  y += render_target->viewport.y;

  /* Use vbeblit_info to encapsulate rendering.  */
  source.mode_info = &bitmap->mode_info;
  source.data = bitmap->data;
  target.mode_info = &render_target->mode_info;
  target.data = render_target->data;

  /* Do actual blitting.  */
  common_blitter (&target, &source, oper, x, y, width, height,
                  offset_x, offset_y);

  return GRUB_ERR_NONE;
}

static grub_err_t
grub_video_vbe_blit_render_target (struct grub_video_render_target *source,
                                   enum grub_video_blit_operators oper,
                                   int x, int y, int offset_x, int offset_y,
                                   unsigned int width, unsigned int height)
{
  struct grub_video_i386_vbeblit_info source_info;
  struct grub_video_i386_vbeblit_info target_info;

  /* Make sure there is something to do.  */
  if ((width == 0) || (height == 0))
    return GRUB_ERR_NONE;
  if ((x >= (int)render_target->viewport.width) || (x + (int)width < 0))
    return GRUB_ERR_NONE;
  if ((y >= (int)render_target->viewport.height) || (y + (int)height < 0))
    return GRUB_ERR_NONE;
  if ((x + (int)source->mode_info.width) < 0)
    return GRUB_ERR_NONE;
  if ((y + (int)source->mode_info.height) < 0)
    return GRUB_ERR_NONE;
  if ((offset_x >= (int)source->mode_info.width) 
      || (offset_x + (int)width < 0))
    return GRUB_ERR_NONE;
  if ((offset_y >= (int)source->mode_info.height) 
      || (offset_y + (int)height < 0))
    return GRUB_ERR_NONE;

  /* If we have negative coordinates, optimize drawing to minimum.  */
  if (offset_x < 0)
    {
      width += offset_x;
      x -= offset_x;
      offset_x = 0;
    }

  if (offset_y < 0)
    {
      height += offset_y;
      y -= offset_y;
      offset_y = 0;
    }

  if (x < 0)
    {
      width += x;
      offset_x -= x;
      x = 0;
    }

  if (y < 0)
    {
      height += y;
      offset_y -= y;
      y = 0;
    }

  /* Do not allow drawing out of viewport.  */
  if ((x + width) > render_target->viewport.width)
    width = render_target->viewport.width - x;
  if ((y + height) > render_target->viewport.height)
    height = render_target->viewport.height - y;

  if ((offset_x + width) > source->mode_info.width)
    width = source->mode_info.width - offset_x;
  if ((offset_y + height) > source->mode_info.height)
    height = source->mode_info.height - offset_y;

  /* Limit drawing to source render target dimensions.  */
  if (width > source->mode_info.width)
    width = source->mode_info.width;

  if (height > source->mode_info.height)
    height = source->mode_info.height;

  /* Add viewport offset.  */
  x += render_target->viewport.x;
  y += render_target->viewport.y;

  /* Use vbeblit_info to encapsulate rendering.  */
  source_info.mode_info = &source->mode_info;
  source_info.data = source->data;
  target_info.mode_info = &render_target->mode_info;
  target_info.data = render_target->data;

  /* Do actual blitting.  */
  common_blitter (&target_info, &source_info, oper, x, y, width, height, 
                  offset_x, offset_y);

  return GRUB_ERR_NONE;
}

static grub_err_t
grub_video_vbe_scroll (grub_video_color_t color, int dx, int dy)
{
  int width;
  int height;
  int src_x;
  int src_y;
  int dst_x;
  int dst_y;

  /* 1. Check if we have something to do.  */
  if ((dx == 0) && (dy == 0))
    return GRUB_ERR_NONE;

  width = render_target->viewport.width - grub_abs (dx);
  height = render_target->viewport.height - grub_abs (dy);

  if (dx < 0)
    {
      src_x = render_target->viewport.x - dx;
      dst_x = render_target->viewport.x;
    }
  else
    {
      src_x = render_target->viewport.x;
      dst_x = render_target->viewport.x + dx;
    }

  if (dy < 0)
    {
      src_y = render_target->viewport.y - dy;
      dst_y = render_target->viewport.y;
    }
  else
    {
      src_y = render_target->viewport.y;
      dst_y = render_target->viewport.y + dy;
    }

  /* 2. Check if there is need to copy data.  */
  if ((grub_abs (dx) < render_target->viewport.width) 
       && (grub_abs (dy) < render_target->viewport.height))
    {
      /* 3. Move data in render target.  */
      struct grub_video_i386_vbeblit_info target;
      grub_uint8_t *src;
      grub_uint8_t *dst;
      int j;

      target.mode_info = &render_target->mode_info;
      target.data = render_target->data;

      for (j = 0; j < height; j++)
        {
          dst = grub_video_vbe_get_video_ptr (&target, dst_x, dst_y + j);
          src = grub_video_vbe_get_video_ptr (&target, src_x, src_y + j);
          grub_memmove (dst, src,
                        width * target.mode_info->bytes_per_pixel);
        }
    }

  /* 4. Fill empty space with specified color.  In this implementation
     there might be colliding areas but at the moment there is no need
     to optimize this.  */

  /* 4a. Fill top & bottom parts.  */
  if (dy > 0)
    grub_video_vbe_fill_rect (color, 0, 0, render_target->viewport.width, dy);
  else if (dy < 0)
    {
      if (render_target->viewport.height < grub_abs (dy))
        dy = -render_target->viewport.height;

      grub_video_vbe_fill_rect (color, 0, render_target->viewport.height + dy,
                                render_target->viewport.width, -dy);
    }

  /* 4b. Fill left & right parts.  */
  if (dx > 0)
    grub_video_vbe_fill_rect (color, 0, 0, 
                              dx, render_target->viewport.height);
  else if (dx < 0)
    {
      if (render_target->viewport.width < grub_abs (dx))
        dx = -render_target->viewport.width;

      grub_video_vbe_fill_rect (color, render_target->viewport.width + dx, 0,
                                -dx, render_target->viewport.height);
    }

  return GRUB_ERR_NONE;
}

static grub_err_t 
grub_video_vbe_swap_buffers (void)
{
  /* TODO: Implement buffer swapping.  */
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_video_vbe_create_render_target (struct grub_video_render_target **result,
                                     unsigned int width, unsigned int height,
                                     unsigned int mode_type)
{
  struct grub_video_render_target *target;
  unsigned int size;

  /* Validate arguments.  */
  if ((! result)
      || (width == 0)
      || (height == 0))
    return grub_error (GRUB_ERR_BAD_ARGUMENT,
                       "invalid argument given.");

  /* Allocate memory for render target.  */
  target = grub_malloc (sizeof (struct grub_video_render_target));
  if (! target)
    return grub_errno;

  /* TODO: Implement other types too.
     Currently only 32bit render targets are supported.  */

  /* Mark render target as allocated.  */
  target->is_allocated = 1;

  /* Maximize viewport.  */
  target->viewport.x = 0;
  target->viewport.y = 0;
  target->viewport.width = width;
  target->viewport.height = height;

  /* Setup render target format.  */
  target->mode_info.width = width;
  target->mode_info.height = height;
  target->mode_info.mode_type = GRUB_VIDEO_MODE_TYPE_RGB 
                                | GRUB_VIDEO_MODE_TYPE_ALPHA;
  target->mode_info.bpp = 32;
  target->mode_info.bytes_per_pixel = 4;
  target->mode_info.pitch = target->mode_info.bytes_per_pixel * width;
  target->mode_info.number_of_colors = 256; /* Emulated paletted.  */
  target->mode_info.red_mask_size = 8;
  target->mode_info.red_field_pos = 0;
  target->mode_info.green_mask_size = 8;
  target->mode_info.green_field_pos = 8;
  target->mode_info.blue_mask_size = 8;
  target->mode_info.blue_field_pos = 16;
  target->mode_info.reserved_mask_size = 8;
  target->mode_info.reserved_field_pos = 24;

  target->mode_info.blit_format = grub_video_get_blit_format (&target->mode_info);

  /* Calculate size needed for the data.  */
  size = (width * target->mode_info.bytes_per_pixel) * height;

  target->data = grub_malloc (size);
  if (! target->data)
    {
      grub_free (target);
      return grub_errno;
    }

  /* Clear render target with black and maximum transparency.  */
  grub_memset (target->data, 0, size);

  /* TODO: Add render target to render target list.  */

  /* Save result to caller.  */
  *result = target;

  return GRUB_ERR_NONE;
}

static grub_err_t
grub_video_vbe_delete_render_target (struct grub_video_render_target *target)
{
  /* If there is no target, then just return without error.  */
  if (! target)
    return GRUB_ERR_NONE;

  /* TODO: Delist render target fron render target list.  */

  /* If this is software render target, free it's memory.  */
  if (target->is_allocated)
    grub_free (target->data);

  /* Free render target.  */
  grub_free (target);

  return GRUB_ERR_NONE;
}

static grub_err_t
grub_video_vbe_set_active_render_target (struct grub_video_render_target *target)
{
  if (target == GRUB_VIDEO_RENDER_TARGET_FRONT_BUFFER)
    {
      render_target = &framebuffer.render_target;

      return GRUB_ERR_NONE;
    }

  if (target == GRUB_VIDEO_RENDER_TARGET_BACK_BUFFER)
    return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, 
                       "double buffering not implemented yet.");

  if (! target->data)
    return grub_error (GRUB_ERR_BAD_ARGUMENT, 
                       "invalid render target given.");

  render_target = target;

  return GRUB_ERR_NONE;
}

static struct grub_video_adapter grub_video_vbe_adapter =
  {
    .name = "VESA BIOS Extension Video Driver",

    .init = grub_video_vbe_init,
    .fini = grub_video_vbe_fini,
    .setup = grub_video_vbe_setup,
    .get_info = grub_video_vbe_get_info,
    .set_palette = grub_video_vbe_set_palette,
    .get_palette = grub_video_vbe_get_palette,
    .set_viewport = grub_video_vbe_set_viewport,
    .get_viewport = grub_video_vbe_get_viewport,
    .map_color = grub_video_vbe_map_color,
    .map_rgb = grub_video_vbe_map_rgb,
    .map_rgba = grub_video_vbe_map_rgba,
    .fill_rect = grub_video_vbe_fill_rect,
    .blit_glyph = grub_video_vbe_blit_glyph,
    .blit_bitmap = grub_video_vbe_blit_bitmap,
    .blit_render_target = grub_video_vbe_blit_render_target,
    .scroll = grub_video_vbe_scroll,
    .swap_buffers = grub_video_vbe_swap_buffers,
    .create_render_target = grub_video_vbe_create_render_target,
    .delete_render_target = grub_video_vbe_delete_render_target,
    .set_active_render_target = grub_video_vbe_set_active_render_target,

    .next = 0
  };

GRUB_MOD_INIT(video_i386_pc_vbe)
{
  grub_video_register (&grub_video_vbe_adapter);
}

GRUB_MOD_FINI(video_i386_pc_vbe)
{
  grub_video_unregister (&grub_video_vbe_adapter);
}