explainroo 0.4: a camera that follows the narration

explainroo 0.4 films each scene with a camera. Until now each scene was one fixed frame, and a small diagram often sat in a corner of an empty frame.

How the camera moves

Before anything is drawn, explainroo measures each element of a scene: where it is, how big it is and when it is on screen. The camera opens on the picture and widens when something new would not fit. Something new that already fits the shot needs no move, so a line added to a chart does not make the camera zoom.

Now and then the camera moves in on what the voice talks about, when the viewer has time to look. Near the end of the scene it pulls back, so the last frame shows the whole idea. While a shot holds, cards and labels are never cut in half.

Highlighted code lines and terminal commands get close-ups when they are small in the shot, and s.focus points the camera at any part of the picture. See how the camera works.

Motion

Things arrive with a little spring, and cards cast a deeper shadow while they land. Final renders add motion blur to frames where something moves, like a film camera. They take about two to three times as long as before. Drafts skip the blur, so they stay quick.

Projects you made before get the camera when you render them again. To keep the fixed frames, set "camera": "still" in video.json. "motionBlur": false turns off the motion blur. See settings.

The release notes and two example videos made with 0.4 are on GitHub.