[patch] implement fading

[Ben Hutchings]

On Wed, 2010-01-27 at 16:31 +0100, Wouter Verhelst wrote:
> diff --git a/src/mixer.cpp b/src/mixer.cpp
> index d4e9d26..6fe782a 100644
> --- a/src/mixer.cpp
> +++ b/src/mixer.cpp
> @@ -35,6 +35,7 @@ struct mixer::video_mix
>      virtual void set_active(const mixer &, bool active) = 0;
>      virtual void apply(const mix_data &, const auto_codec &,
>  		       raw_frame_ptr &, dv_frame_ptr &) = 0;
> +    virtual void set_monitor(monitor*) = 0;

video_mix should not be coupled to monitor.  Instead, make apply()
return a flag whenever the effect state changes, and run_mixer() can
then poke the monitor when it's true.

[...]
> +    void set_scale(uint8_t scale) { scale_ = scale; };

A video_mix may be shared between all items in the mixer queue, so it
must never be modified once it has been created - except that
transitions can be updated by the apply() function.  When you implement
manual adjustment by the user this must be done by creating new objects.

> +    uint8_t get_scale() { return scale_; };

Add a blank line here.

> +private:
> +    virtual void validate(const mixer &);
> +    virtual void set_active(const mixer &, bool active);
> +    virtual void apply(const mix_data &, const auto_codec &, raw_frame_ptr &, dv_frame_ptr &);
> +    virtual void set_monitor(mixer::monitor* m);

Add a blank line here.

> +    mixer::monitor* monitor_;
> +    source_id pri_source_id_, sec_source_id_;
> +    bool timed_;
> +    uint8_t scale_;
> +    int bucketsize_;
> +    int modulo_;
> +    int ms_per_frame_;
> +};
> +
> +void mixer::video_mix_fade::set_monitor(mixer::monitor* m)
> +{
> +    monitor_ = m;
> +}
> +
> +// these two were shamelessly copied from video_mix_pic_in_pic -- perhaps that
> +// should be generalized?

No need for such comments in the code.

[...]
> +void mixer::video_mix_fade::apply(const mix_data & m,
> +				  const auto_codec & decoder,
> +				  raw_frame_ptr & mixed_raw,
> +				  dv_frame_ptr &)
> +{
> +    const dv_frame_ptr & pri_source_dv = m.source_frames[pri_source_id_];
> +    const dv_frame_ptr & sec_source_dv = m.source_frames[sec_source_id_];
> +
> +    if (timed_)
> +    {
> +        int val;
> +	int step;

Use tabs consistently for indenting by 8 spaces.

> +    	if (!ms_per_frame_)
> +	{
> +	    ms_per_frame_ = (1000 * m.format.system->frame_rate_denom) / m.format.system->frame_rate_numer;
> +	}
> +	val = modulo_ + ms_per_frame_;
> +	step = val / bucketsize_;
> +	modulo_ = val % bucketsize_;
> +	if ((scale_+step) >= 255) {
[...]

Put a space on either side of '+' and all other binary operators.
Put each opening brace on a new line.

Ben.

-- 
Ben Hutchings
The most exhausting thing in life is being insincere. - Anne Morrow Lindberg
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