uterm: video: add blitting support

All backends that do not provide OpenGL contexts can not implement buffer
blitting so we can at least draw rectangular areas to the framebuffer.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

src/uterm.h

@@ -157,6 +157,14 @@ struct uterm_video_hotplug {
 	int action;
 };
 
+struct uterm_video_buffer {
+	uint8_t *data;
+	unsigned int width;
+	unsigned int height;
+	unsigned int stride;
+	unsigned int bpp;
+};
+
 typedef void (*uterm_video_cb) (struct uterm_video *video,
 				struct uterm_video_hotplug *arg,
 				void *data);
@@ -177,6 +185,10 @@ unsigned int uterm_screen_height(struct uterm_screen *screen);
 
 int uterm_screen_use(struct uterm_screen *screen);
 int uterm_screen_swap(struct uterm_screen *screen);
+int uterm_screen_blit(struct uterm_screen *screen,
+		      const struct uterm_video_buffer *buf,
+		      unsigned int x, unsigned int y,
+		      unsigned int width, unsigned int height);
 
 /* display modes interface */
 

src/uterm_video.c

@@ -134,6 +134,18 @@ int uterm_screen_swap(struct uterm_screen *screen)
 	return VIDEO_CALL(screen->disp->ops->swap, 0, screen->disp);
 }
 
+int uterm_screen_blit(struct uterm_screen *screen,
+		      const struct uterm_video_buffer *buf,
+		      unsigned int x, unsigned int y,
+		      unsigned int width, unsigned int height)
+{
+	if (!screen)
+		return -EINVAL;
+
+	return VIDEO_CALL(screen->disp->ops->blit, -EOPNOTSUPP, screen->disp,
+			  buf, x, y, width, height);
+}
+
 int mode_new(struct uterm_mode **out, const struct mode_ops *ops)
 {
 	struct uterm_mode *mode;

src/uterm_video_fbdev.c

@@ -319,6 +319,51 @@ static int display_swap(struct uterm_display *disp)
 	return 0;
 }
 
+static int display_blit(struct uterm_display *disp,
+			const struct uterm_video_buffer *buf,
+			unsigned int x, unsigned int y,
+			unsigned int width, unsigned int height)
+{
+	unsigned int tmp;
+	uint8_t *dst, *src;
+
+	log_debug("blit start");
+	if (!disp->video || !(disp->flags & DISPLAY_ONLINE))
+		return -EINVAL;
+	if (!buf || !video_is_awake(disp->video))
+		return -EINVAL;
+	if (buf->bpp != disp->fbdev.bpp)
+		return -EINVAL;
+
+	tmp = x + width;
+	if (tmp < x || x >= buf->width)
+		return -EINVAL;
+	if (tmp > buf->width)
+		width = buf->width - x;
+	tmp = y + height;
+	if (tmp < y || y >= buf->height)
+		return -EINVAL;
+	if (tmp > buf->height)
+		height = buf->height - y;
+
+	if (disp->fbdev.bufid)
+		dst = disp->fbdev.map;
+	else
+		dst = &disp->fbdev.map[disp->fbdev.yres * disp->fbdev.stride];
+	dst = &dst[y * disp->fbdev.stride + x * disp->fbdev.bpp];
+	src = &buf->data[y * buf->stride + x * buf->bpp];
+
+	log_debug("blitting %u %u %u %u %u %u", buf->width, buf->height,
+		x, y, width, height);
+	while (--height) {
+		memcpy(dst, src, buf->bpp * width);
+		dst += disp->fbdev.stride;
+		src += buf->stride;
+	}
+
+	return 0;
+}
+
 static int video_init(struct uterm_video *video, const char *node)
 {
 	int ret;
@@ -405,6 +450,7 @@ const struct display_ops fbdev_display_ops = {
 	.set_dpms = display_set_dpms,
 	.use = NULL,
 	.swap = display_swap,
+	.blit = display_blit,
 };
 
 const struct video_ops fbdev_video_ops = {