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liquid_fb: Improve resize handling 

This patch make the handling of resizing the virtual framebuffer more
consistent. Liquid_fb keeps track of two sizes. The "next size" is the
size of the framebuffer handed out via the next call of 'dataspace'.
The "designated size" is the size as demanded by the user. The latter
size may be updated more often than the "next" size, depending on the
responsiveness of the framebuffer client to mode-change signals.

The patch also removes the synchronization with refresh calls because
the synchronization made the flickering artifacts worse when executing
nitpicker within liquid_fb. So it was not properly working anyway.
In the future, we might reimplement such a synchronization mechanism
when switching to the server API.

Issue #1056
This commit is contained in:
Norman Feske 2014-02-11 15:04:22 +01:00
parent 4a61d008be
commit 0056167157
1 changed files with 40 additions and 33 deletions
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73
demo/src/server/liquid_framebuffer/services.cc
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@ -176,9 +176,25 @@ class Window_content : public Scout::Element
bool _config_alpha;
Content_event_handler _ev_handler;
Fb_texture *_fb;
unsigned _new_w, _new_h;
/**
* Size of the framebuffer handed out by the next call of 'dataspace'
*/
Scout::Area _next_size;
/**
* Most current designated size of the framebuffer as defined by the
* user.
*
* The '_designated_size' may be updated any time when the user drags
* the resize handle of the window. It is propagated to '_next_size'
* not before the framebuffer client requests the current mode. Once
* the mode information is passed to the client, it is locked until
* the client requests the mode again.
*/
Scout::Area _designated_size;
Genode::Signal_context_capability _mode_sigh;
bool _wait_for_refresh;
public:
@ -188,23 +204,23 @@ class Window_content : public Scout::Element
_config_alpha(config_alpha),
_ev_handler(ev_queue, this),
_fb(new (Genode::env()->heap()) Fb_texture(fb_w, fb_h, _config_alpha)),
_new_w(fb_w), _new_h(fb_h),
_wait_for_refresh(false)
_next_size(fb_w, fb_h),
_designated_size(_next_size)
{
_min_size = Scout::Area(_fb->w, _fb->h);
event_handler(&_ev_handler);
}
Genode::Dataspace_capability fb_ds_cap() {
return _fb->ds.cap();
}
Genode::Dataspace_capability fb_ds_cap() { return _fb->ds.cap(); }
unsigned fb_w() {
return _fb->w;
}
unsigned fb_h() {
return _fb->h;
unsigned fb_w() { return _fb->w; }
unsigned fb_h() { return _fb->h; }
Scout::Area mode_size()
{
_next_size = _designated_size;
return _next_size;
}
void mode_sigh(Genode::Signal_context_capability sigh)
@ -215,36 +231,26 @@ class Window_content : public Scout::Element
void realloc_framebuffer()
{
/* skip reallocation if size has not changed */
if (_new_w == _fb->w && _new_h == _fb->h)
if (_next_size.w() == _fb->w && _next_size.h() == _fb->h)
return;
Genode::destroy(Genode::env()->heap(), _fb);
_fb = new (Genode::env()->heap())
Fb_texture(_new_w, _new_h, _config_alpha);
/*
* Suppress drawing of the texture until we received the next
* refresh call from the client. This way, we avoid flickering
* artifacts while continuously resizing the window.
*/
_wait_for_refresh = true;
Fb_texture(_next_size.w(), _next_size.h(), _config_alpha);
}
void client_called_refresh() { _wait_for_refresh = false; }
/**
* Element interface
*/
void draw(Scout::Canvas_base &canvas, Scout::Point abs_position)
{
if (!_wait_for_refresh)
canvas.draw_texture(abs_position + _position, _fb->texture);
canvas.draw_texture(abs_position + _position, _fb->texture);
}
void format_fixed_size(Scout::Area size)
{
_new_w = size.w(), _new_h = size.h();
_designated_size = size;
/* notify framebuffer client about mode change */
if (_mode_sigh.valid())
@ -275,16 +281,18 @@ namespace Framebuffer
Session_component(Window_content &window_content)
: _window_content(window_content) { }
Genode::Dataspace_capability dataspace() {
return _window_content.fb_ds_cap(); }
Genode::Dataspace_capability dataspace()
{
_window_content.realloc_framebuffer();
return _window_content.fb_ds_cap();
}
void release() {
_window_content.realloc_framebuffer(); }
void release() { }
Mode mode() const
{
return Mode(_window_content.fb_w(), _window_content.fb_h(),
Mode::RGB565);
return Mode(_window_content.mode_size().w(),
_window_content.mode_size().h(), Mode::RGB565);
}
void mode_sigh(Genode::Signal_context_capability sigh) {
@ -292,7 +300,6 @@ namespace Framebuffer
void refresh(int x, int y, int w, int h)
{
_window_content.client_called_refresh();
_window_content.redraw_area(x, y, w, h);
}
};