maintainRatio = effect("Maintain Ratio")("Checkbox");
fillMode = effect("Fit / Fill")("Checkbox");
lw = thisLayer.width;
lh = thisLayer.height;
cw = thisComp.width;
ch = thisComp.height;
aspectLayer = lw / lh;
aspectComp = cw / ch;
if (maintainRatio == 1){
if (fillMode == 0){
// FIT (contain without cropping)
scaleFactor = Math.min(cw / lw, ch / lh);
[scaleFactor * 100, scaleFactor * 100];}
else {
// FILL (cover full comp, may crop)
scaleFactor = Math.max(cw / lw, ch / lh);
[scaleFactor * 100, scaleFactor * 100];}}
else {
// No ratio constraint, stretch to fit/fill comp
if (fillMode == 0) {
[cw / lw * 100, ch / lh * 100];
// Fit (stretch)
}
else{
[cw / lw * 100, ch / lh * 100];
// Fill (also stretches in this case)
}}
View all expressions
Transformation
Auto Scale to Comp
Automatically resizes your image, video, or precomp so it fits perfectly inside the composition. You can choose whether it should fit completely inside (no cropping) or fill the entire frame (may crop a bit). There’s also a switch to keep or ignore the original aspect ratio, so you can decide if it should stay proportional or stretch to fill the space.
Contributed by:
Auto Scale to Comp
Practical use case
Use this when you’re replacing footage or images in a template and want them to instantly scale to the right size without guessing. It’s great for social-media versions (square, vertical, or widescreen), product videos, or automated projects where every image needs to fit just right every time.
Data-driven video workflows for After Effects are easier with Plainly.
