add animate-image.php example

Author: jcupitt

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to `:vips` will be documented in this file.
 
 ## master
 
+- added `animate-image.php` example [jcupitt]
+
 ## 2.3.0 - 2023-09-26
 
 - add getFields() to fetch an array of field names [jcupitt]

examples/animate-image.php

@@ -0,0 +1,41 @@
+#!/usr/bin/env php
+<?php
+
+require dirname(__DIR__) . '/vendor/autoload.php';
+use Jcupitt\Vips;
+
+#Vips\Config::setLogger(new Vips\DebugLogger());
+
+if (count($argv) != 4) {
+    echo("usage: ./animate-image.php input-image output-image 'text string'\n");
+    exit(1);
+}
+
+$image = Vips\Image::newFromFile($argv[1]);
+$text = Vips\Image::text($argv[3], ["dpi" => 300, "rgba" => true]);
+$animation = NULL;
+$delay = [];
+
+for ($x = 0; $x < $image->width + $text->width; $x += 10)
+{
+    // append the frame to the image vertically ... we make a very tall, thin
+    // strip of frames to save
+    $frame = $image->composite2($text, "over", [
+        "x" => $x - $text->width,
+        "y" => $image->height / 2 - $text->height / 2
+    ]);
+    if ($animation == NULL)
+        $animation = $frame;
+    else
+        $animation = $animation->join($frame, "vertical");
+
+    // frame delay in ms
+    array_push($delay, 30);
+}
+
+// set animation properties
+$animation->set("delay", $delay);
+$animation->set("loop", 0);
+$animation->set("page-height", $image->height);
+
+$animation->writeToFile($argv[2]);