gui: image_renderer: fix "no previous prototype for 'image_renderer_unregister'" warning ...

The patch fixes this compiler's warning:

  lib/gui/image_renderer.c:92:6: warning: no previous prototype for 'image_renderer_unregister' [-Wmissing-prototypes]
   void image_renderer_unregister(struct image_renderer *ir)
        ^

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

GUI: Add code to draw simple graphics ...

Add code to draw simple graphics, namely lines(solid or dashed) and
circles.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

GUI: Add a function to draw vertical/horizontal bars ...

Add a function to draw solid vertical or horizontal bars.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: implement blitting screen areas ...

So far we only supported blitting the whole screen from the shadow
fb to the framebuffer. Add a function to blit areas.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: Use fb provided shadowfb for offscreen rendering ...

The fb core now has builtin support for offscreen rendering, use
this and drop offscreen handling in the gui code.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

graphics_utils: Let fb_open allocate the screen ...

Allocate the screen dynamically in fb_open. This opens the way to create
a fb_create_screen function which takes a struct fb_info * instead of a
filename. This is suitable for the framebuffer console which already has
a struct fb_info *.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

graphics_utils: add function to create pixel from rgb triplet ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

graphics_utils: Export get_pixel ...

get_pixel converts a 32bit trgb color into framebuffer format. This
is useful for other code aswell, so export it.
Other functions in the graphics utils code use the name get/set_pixel
aswell, but instead of converting data they get a pixel from the framebuffer
or set a pixel on the framebuffer. To separate from these rename the
function to gu_hex_to_pixel.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

graphics_utils: Add function to invert an area ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: Fix typo in function name ...

It's a render buffer, not a redering buffer.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

graphic_utils: Add a common namespace to functions ...

This adds a common namespace to the graphic functions. We use
gu_ for graphic_utils.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: blit the surface on demand ...

Do not blit the surface everytime we write an image
As we want to able to render multiple image this will cause 1 blit per image;

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

graphic_utils: introduce common fb_open/close ...

To open, memmap, get the fb_info and if needed allocate the offscreen buffer

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: introduce screen and surface to factorize and simplify code ...

Instead of passing hundreds of parameter, just pass the right structure.

struct screen represent the screen with a without double buffering.
struct surface represent the part of the screen we want to render.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

graphic_utils: pass image so we can draw only the visible part of the image ...

This is needed if the image is bigger than the screen.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

gui: move gui file to include/gui and lib/gui ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>