[CinCV TNG] [impr] FindObj plugin part 2

Sam cinelerra at posteo.de
Sun Apr 15 01:43:12 CEST 2018

I needed the line in the previous version of the FindObj plugin to align 
the frame around the object. With the new version it is no longer 
necessary, because the drag box does this task. I don't need thicker 
lines anymore.
Sorry, I forgot to report that point as done.
I will finish the tutorial tomorrow, I was still busy with the new 
control buttons and the new Cinfintiy design.


On 14.04.2018 23:56, Phyllis Smith wrote:
> The latest GIT checkin has another whole column added for Replace Object.
> I can't even begin to figure it out so am waiting to see Sam's tutorial!ed
> However, GG says it should do just about everything.  About the 
> disappearing lines, GG says:
> The draw border checkbox functions cause an enclosing rectangle to be 
> drawn around
> the corresponding region of interest.  The lines drawn are 1 pixel 
> wide, and are drawn
> into the media output. This makes them visible on the composer as 
> image data, BUT
> the composer is usually drawn downscaled.  ie the media is 1920x1080, 
> but the composer
> is drawn 800x500.  This causes about every other line to disappear, 
> both horizontally and
> vertically.  This regular data interference pattern is commonly called 
> aliasing.  It creates a
> regular beat frequency and creates a comb like pattern, or the "alias" 
> frequency on data.
> To avoid aliasing, the data sample has to be bigger than the sample 
> size, in this case
> ceiling(1920/800) or 3px wide, or the aliasing could delete the line 
> field.  Since the draw
> border function is just one pixel wide, it is very susceptible to this 
> problem.  Since the
> drag lines are drawn as composer objects, an extra step is used to 
> beef up the line
> thickness.  If the draw border data is needed for media output (in the 
> rendering), then
> 1px is a good idea.  If the draw border data is needed for composer 
> work, then it
> should also be beefed up.  So... how are you using these lines?
> On Thu, Apr 12, 2018 at 2:04 PM, Sam <cinelerra at posteo.de 
> <mailto:cinelerra at posteo.de>> wrote:
>     Here is a summary:
>     1. make size reduction of the replacement layer optional.
>     2. add replace object frame. (It already exists, but cannot be
>     changed.)
>     3. keep the relative offset to the replacement frame to the object.
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