How to get the input data on the arbitrary draw event ?

Question

Hi all,
I'm trying to draw a histogram on a arbitrary parameter (just like the "Levels" effect). The draw part is well, but I have a problem with the input layer data (param[0]).
All I have to do now is read the input data on the arbitrary draw event. But there's not the input pointer on the draw event. So I called the PF_CHECKOUT_PARAM() function to get the input data, and it works!
When I test in AE, I created a layer A, and added some color correction effects to the layer A before added my effect to the layer A. The problem is the input layer my effect read is not the result of previous effects I applied before.
Has anyway to read the latest input data in the arbitrary events ?
Thanks.

Answer 1

Hi shachar, nice to meet you!
In another way, I created a sequence data like this:
typedef struct {
    bool didRender;
    <some histogram data>;
} Histogram;
typedef struct {
    Histogram*  histograms;
} my_sequence_data, *my_sequence_dataP, **my_sequence_dataH;
my_sequence_data.histograms is an array with in_data->total_time / in_data->time_step items initialized during the sequence setup.
During the render call, I cached  the calculated histogram at this current_time to the sequence->histograms[in_data->current_time / in_data->time_step], set the didRender = true.
In this way, I have another problem with the AE cached image. I disabled a random previous effect on the effect panel, then the AE re-rendered my effect, the histogram changed (good). I enabled the effect again, and nothing change (bad )
I try to force the AE re-rendering after the custom UI changed ( I tried with the event_extraP->evt_out_flags = PF_EO_HANDLED_EVENT; and params[HISTOGRAM_UI]->uu.change_flags |= PF_ChangeFlag_CHANGED_VALUE; on the click, drag events...) but it seem not works!
Am I on the right way ?
Thank you so much!