1.算法程序
AfterEffect(AE)插件是Adobe公司开发的特效制作软件，稳定快速的功能和特效，在视频制作领域使用非常广泛，本文向大家介绍如何在项目里进行合成放大缩小功能。源代码如下所示：
{
// Scale Composition.jsx
//
// This script scales the active comp and all the layers within it.
//
// First, it prompts the user for a scale_factor, a new comp width,
// or a new comp height.
//
// Next, it scales the comp and all the layers within it, including
// cameras.
function ScaleComposition(thisObj)
{
var scriptName = "Scale Composition";
// This variable stores the scale_factor.
var scale_factor = 1.0;
var text_input = null;
var scaleButton = null;
var widthButton = null;
var heightButton = null;
function onScaleButtonClick()
{
this.parent.text_input.text = scale_factor;
}
function onWidthButtonClick()
{
var activeItem = app.project.activeItem;
if ((activeItem == null) || !(activeItem instanceof CompItem)) {
alert("Please select or open a composition first.", scriptName);
} else {
this.parent.text_input.text = Math.floor(activeItem.width * scale_factor);
}
}
function onHeightButtonClick()
{
var activeItem = app.project.activeItem;
if ((activeItem == null) || !(activeItem instanceof CompItem)) {
alert("Please select or open a composition first.", scriptName);
} else {
this.parent.text_input.text = Math.floor(activeItem.height * scale_factor);
}
}
function testNewScale(test_scale)
{
var is_ok = true;
var activeItem = app.project.activeItem;
if ((activeItem == null) || !(activeItem instanceof CompItem)) {
alert("Please select or open a composition first.", scriptName);
} else {
if (test_scale * activeItem.width < 1 || test_scale * activeItem.width > 30000) {
is_ok = false;
} else if (test_scale * activeItem.height < 1 || test_scale * activeItem.height > 30000) {
is_ok = false;
}
}
return is_ok;
}
//
// This function is called when the user enters text for the scale.
//
function on_textInput_changed()
{
var activeItem = app.project.activeItem;
if ((activeItem == null) || !(activeItem instanceof CompItem)) {
alert("Please select or open a composition first.", scriptName);
} else {
// Set the scale_factor based on the text.
var value = this.text;
if (isNaN(value)) {
alert(value + " is not a number. Please enter a number.", scriptName);
} else {
var new_scale_factor;
if (this.parent.scaleButton.value == true) {
new_scale_factor = value;
} else if (this.parent.widthButton.value == true) {
new_scale_factor = value / activeItem.width;
} else {
new_scale_factor = value / activeItem.height;
}
if (testNewScale(new_scale_factor)) {
scale_factor = new_scale_factor;
} else {
alert("Value will make height or width out of range 1 to 30000. Reverting to previous value.", scriptName);
// Load text back in from current values.
if (scaleButton.value == true) {
onScaleButtonClick();
} else if (widthButton.value == true) {
onWidthButtonClick();
} else {
onHeightButtonClick();
}
}
}
}
}
function onScaleClick()
{
var activeItem = app.project.activeItem;
if ((activeItem == null) || !(activeItem instanceof CompItem)) {
alert("Please select or open a composition first.", scriptName);
} else {
// Validate the input field, in case the user didn't defocus it first (which often can be the case).
this.parent.parent.optsRow.text_input.notify("onChange");
var activeComp = activeItem;
// By bracketing the operations with begin/end undo group, we can
// undo the whole script with one undo operation.
app.beginUndoGroup(scriptName);
// Create a null 3D layer.
var null3DLayer = activeItem.layers.addNull();
null3DLayer.threeDLayer = true;
// Set its position to (0,0,0).
null3DLayer.position.setValue([0,0,0]);
// Set null3DLayer as parent of all layers that don't have parents.
makeParentLayerOfAllUnparented(activeComp, null3DLayer);
// Set new comp width and height.
activeComp.width = Math.floor(activeComp.width * scale_factor);
activeComp.height = Math.floor(activeComp.height * scale_factor);
// Then for all cameras, scale the Zoom parameter proportionately.
scaleAllCameraZooms(activeComp, scale_factor);
// Set the scale of the super parent null3DLayer proportionately.
var superParentScale = null3DLayer.scale.value;
superParentScale[0] = superParentScale[0] * scale_factor;
superParentScale[1] = superParentScale[1] * scale_factor;
superParentScale[2] = superParentScale[2] * scale_factor;
null3DLayer.scale.setValue(superParentScale);
// Delete the super parent null3DLayer with dejumping enabled.
null3DLayer.remove();
app.endUndoGroup();
// Reset scale_factor to 1.0 for next use.
scale_factor = 1.0;
if (this.parent.parent.optsRow.scaleButton.value) {
this.parent.parent.optsRow.text_input.text = "1.0";
}
}
}
//
// This function puts up a modal dialog asking for a scale_factor.
// Once the user enters a value, the dialog closes, and the script scales the comp.
//
function BuildAndShowUI(thisObj)
{
// Create and show a floating palette.
var my_palette = (thisObj instanceof Panel) ? thisObj : new Window("palette", scriptName, undefined, {resizeable:true});
if (my_palette != null)
{
var res =
"group { \
orientation:'column', alignment:['fill','top'], alignChildren:['left','top'], spacing:5, margins:[0,0,0,0], \
introStr: StaticText { text:'Scale composition using:', alignment:['left','center'] }, \
optsRow: Group { \
orientation:'column', alignment:['fill','top'], \
scaleButton: RadioButton { text:'New Scale Factor', alignment:['fill','top'], value:'true' }, \
widthButton: RadioButton { text:'New Comp Width', alignment:['fill','top'] }, \
heightButton: RadioButton { text:'New Comp Height', alignment:['fill','top'] }, \
text_input: EditText { text:'1.0', alignment:['left','top'], preferredSize:[80,20] }, \
}, \
cmds: Group { \
alignment:['fill','top'], \
okButton: Button { text:'Scale', alignment:['fill','center'] }, \
}, \
}";
my_palette.margins = [10,10,10,10];
my_palette.grp = my_palette.add(res);
// Workaround to ensure the edittext text color is black, even at darker UI brightness levels.
var winGfx = my_palette.graphics;
var darkColorBrush = winGfx.newPen(winGfx.BrushType.SOLID_COLOR, [0,0,0], 1);
my_palette.grp.optsRow.text_input.graphics.foregroundColor = darkColorBrush;
my_palette.grp.optsRow.scaleButton.onClick = onScaleButtonClick;
my_palette.grp.optsRow.widthButton.onClick = onWidthButtonClick;
my_palette.grp.optsRow.heightButton.onClick = onHeightButtonClick;
// Set the callback. When the user enters text, this will be called.
my_palette.grp.optsRow.text_input.onChange = on_textInput_changed;
my_palette.grp.cmds.okButton.onClick = onScaleClick;
my_palette.onResizing = my_palette.onResize = function () {this.layout.resize();}
}
return my_palette;
}
//
// Sets newParent as the parent of all layers in theComp that don't have parents.
// This includes 2D/3D lights, camera, av, text, etc.
//
function makeParentLayerOfAllUnparented(theComp, newParent)
{
for (var i = 1; i <= theComp.numLayers; i++) {
var curLayer = theComp.layer(i);
var wasLocked = curLayer.locked;
curLayer.locked = false;
if (curLayer != newParent && curLayer.parent == null) {
curLayer.parent = newParent;
}
curLayer.locked = wasLocked
}
}
//
// Scales the zoom factor of every camera by the given scale_factor.
// Handles both single values and multiple keyframe values.
function scaleAllCameraZooms(theComp, scaleBy)
{
for (var i = 1; i <= theComp.numLayers; i++) {
var curLayer = theComp.layer(i);
if (curLayer.matchName == "ADBE Camera Layer") {
var curZoom = curLayer.zoom;
if (curZoom.numKeys == 0) {
curZoom.setValue(curZoom.value * scaleBy);
} else {
for (var j = 1; j <= curZoom.numKeys; j++) {
curZoom.setValueAtKey(j,curZoom.keyValue(j)*scaleBy);
}
}
}
}
}
//
// The main script.
//
if (parseFloat(app.version) < 8) {
alert("This script requires After Effects CS3 or later.", scriptName);
return;
}
var my_palette = BuildAndShowUI(thisObj);
if (my_palette != null) {
if (my_palette instanceof Window) {
my_palette.center();
my_palette.show();
} else {
my_palette.layout.layout(true);
my_palette.layout.resize();
}
} else {
alert("Could not open the user interface.", scriptName);
}
}
ScaleComposition(this);
}
2.作者答疑
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