在 PHP 中从演示文稿形状提取图像

概述

演示文稿中的图像可以以多种形状类型出现：普通图片框、应用于形状的图片填充、OLE 对象预览图像、视频或音频帧缩略图、缩放图像，或嵌套在表格、图表和 SmartArt 形状内的图像。Aspose.Slides 将这些图像存储在演示文稿的图像集合中，可通过 ImageCollection 和 PPImage 对象访问。

如果您只需要导出演示文稿中嵌入的每个图像资源，只需遍历 presentation->getImages()。本文侧重于另一项任务：遍历形状以查找幻灯片中使用图像的位置，从而保存的文件能够保留有用的上下文信息，如幻灯片编号、形状位置和来源类型（图片框、填充图像、媒体预览、OLE 预览或缩放图像）。

Tip

使用 PPImage 及其 getBinaryData() 方法来保留原始编码的图像数据和文件类型。当需要将输出统一为特定格式（如 PNG）时，请使用 getImage()。

共享辅助方法

下面的辅助方法可以让示例保持简短。saveOriginalImage 将写入原始嵌入的字节，根据 MIME 类型选择安全的扩展名，并通过 SHA-256 哈希跳过重复的图像二进制数据。

use aspose\slides\FillType;
use aspose\slides\ImageFormat;

class ShapeReference
{
    public $shape;
    public $namePart;

    public function __construct($shape, $namePart)
    {
        $this->shape = $shape;
        $this->namePart = $namePart;
    }
}

function isNullJava($value)
{
    return $value == null || java_is_null($value);
}

function saveOriginalImage($image, $outputDirectory, $fileNameBase, &$savedImageHashes)
{
    if (isNullJava($image)) {
        return false;
    }

    $imageData = $image->getBinaryData();
    $imageBytes = getBinaryString($imageData);
    $imageHash = hash("sha256", $imageBytes);
    if (isset($savedImageHashes[$imageHash])) {
        return false;
    }

    $savedImageHashes[$imageHash] = true;

    $extension = getExtensionFromContentType($image->getContentType());
    $fileName = $fileNameBase . "." . $extension;
    $outputPath = $outputDirectory . DIRECTORY_SEPARATOR . $fileName;
    file_put_contents($outputPath, $imageBytes);
    return true;
}

function saveImageAsPng($image, $outputDirectory, $fileNameBase)
{
    if (isNullJava($image)) {
        return false;
    }

    $fileName = $fileNameBase . ".png";
    $outputPath = $outputDirectory . DIRECTORY_SEPARATOR . $fileName;

    $outputImage = $image->getImage();
    try {
        $outputImage->save($outputPath, ImageFormat::Png);
    } finally {
        if (!isNullJava($outputImage)) {
            $outputImage->dispose();
        }
    }

    return true;
}

function getPictureFillImage($fillFormat)
{
    if (isNullJava($fillFormat) || java_values($fillFormat->getFillType()) != FillType::Picture) {
        return null;
    }

    return $fillFormat->getPictureFillFormat()->getPicture()->getImage();
}

function enumerateShapes($shapes, $prefix, $includeGroupedShapes)
{
    $shapeReferences = [];
    $shapeCount = java_values($shapes->size());
    for ($shapeIndex = 0; $shapeIndex < $shapeCount; $shapeIndex++) {
        $shape = $shapes->get_Item($shapeIndex);
        $displayIndex = $shapeIndex + 1;
        $shapeNamePart = $prefix . "_shape_" . $displayIndex;
        $shapeReferences[] = new ShapeReference($shape, $shapeNamePart);

        if ($includeGroupedShapes && java_instanceof($shape, new JavaClass("com.aspose.slides.GroupShape"))) {
            $childShapes = $shape->getShapes();
            $childReferences = enumerateShapes(
                $childShapes,
                $shapeNamePart,
                $includeGroupedShapes
            );
            $shapeReferences = array_merge($shapeReferences, $childReferences);
        }
    }

    return $shapeReferences;
}

function getBinaryString($binaryData)
{
    $bytes = java_values($binaryData);
    if (is_string($bytes)) {
        return $bytes;
    }

    $binaryString = "";
    foreach ($bytes as $byte) {
        $binaryString .= chr($byte & 0xff);
    }

    return $binaryString;
}

function getExtensionFromContentType($contentType)
{
    if ($contentType == null || strlen(trim($contentType)) == 0) {
        return "bin";
    }

    $mediaTypeParts = explode(";", $contentType);
    $mediaType = strtolower(trim($mediaTypeParts[0]));
    if ($mediaType == "image/jpeg") {
        return "jpg";
    }

    if ($mediaType == "image/png") {
        return "png";
    }

    if ($mediaType == "image/gif") {
        return "gif";
    }

    if ($mediaType == "image/bmp") {
        return "bmp";
    }

    if ($mediaType == "image/tiff") {
        return "tiff";
    }

    if ($mediaType == "image/x-emf" || $mediaType == "image/emf") {
        return "emf";
    }

    if ($mediaType == "image/x-wmf" || $mediaType == "image/wmf") {
        return "wmf";
    }

    if ($mediaType == "image/svg+xml") {
        return "svg";
    }

    if (strpos($mediaType, "image/") === 0) {
        $extension = substr($mediaType, strlen("image/"));
        return makeSafeFileNamePart($extension);
    }

    return "bin";
}

function makeSafeFileNamePart($value)
{
    return preg_replace("/[^A-Za-z0-9._-]/", "_", $value);
}

从图片框提取图像

此方法适用于作为独立对象插入的图片。PictureFrame 将图片存储在 getPictureFormat()->getPicture()->getImage() 中，返回一个 PPImage 对象。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "extracted-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, false);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.PictureFrame"))) {
                $pictureFrame = $shapeReference->shape;
                $image = $pictureFrame->getPictureFormat()->getPicture()->getImage();
                saveOriginalImage($image, $outputDirectory, $shapeReference->namePart, $savedImageHashes);
            }
        }
    }
} finally {
    $presentation->dispose();
}

从填充图片的形状提取图像

形状可以使用图片作为填充。首先检查形状的填充类型：如果不是 FillType.Picture，则该填充中没有可提取的图片。下面的示例处理 AutoShape 对象，并通过 PPImage 及其 getImage() 方法将每个图像保存为 PNG。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "shape-fill-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, false);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.AutoShape"))) {
                $autoShape = $shapeReference->shape;
                $fillFormat = $autoShape->getFillFormat();
                $image = getPictureFillImage($fillFormat);
                if (!isNullJava($image)) {
                    saveImageAsPng($image, $outputDirectory, $shapeReference->namePart);
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从 OLE 对象框提取预览图像

OleObjectFrame 可以拥有 PowerPoint 用作对象在幻灯片上预览的替代图片。该图片可通过 getSubstitutePictureFormat()->getPicture()->getImage() 获取。提取此图片得到的是预览图像，而非嵌入的 OLE 包内容。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "ole-preview-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, false);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.OleObjectFrame"))) {
                $oleObjectFrame = $shapeReference->shape;
                $image = $oleObjectFrame->getSubstitutePictureFormat()->getPicture()->getImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_ole_preview";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从视频帧提取预览图像

VideoFrame 也可以在 getPictureFormat()->getPicture()->getImage() 中存储预览图像。这是幻灯片上显示的海报或缩略图，而非从视频流解码的帧。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "video-preview-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, false);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.VideoFrame"))) {
                $videoFrame = $shapeReference->shape;
                $image = $videoFrame->getPictureFormat()->getPicture()->getImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_video_preview";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从音频帧提取预览图像

AudioFrame 可以在 getPictureFormat()->getPicture()->getImage() 中存储缩略图。这是幻灯片上音频对象显示的图像。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "audio-preview-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, false);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.AudioFrame"))) {
                $audioFrame = $shapeReference->shape;
                $image = $audioFrame->getPictureFormat()->getPicture()->getImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_audio_preview";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从缩放对象提取图像

ZoomFrame 和 SectionZoomFrame 形状可以使用自定义图像。请从缩放框读取 getZoomImage()。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "zoom-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, false);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.ZoomFrame"))) {
                $zoomFrame = $shapeReference->shape;
                $image = $zoomFrame->getZoomImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_zoom";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                    continue;
                }
            }

            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.SectionZoomFrame"))) {
                $sectionZoomFrame = $shapeReference->shape;
                $image = $sectionZoomFrame->getZoomImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_section_zoom";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                    continue;
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从汇总缩放框提取图像

SummaryZoomFrame 同样是一个形状。其各节项目可以使用自定义图像，可通过每个汇总缩放节的 getZoomImage() 方法访问。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "summary-zoom-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, false);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.SummaryZoomFrame"))) {
                $summaryZoomFrame = $shapeReference->shape;
                $summaryZoomCollection = $summaryZoomFrame->getSummaryZoomCollection();
                $sectionCount = java_values($summaryZoomCollection->size());
                for ($sectionIndex = 0; $sectionIndex < $sectionCount; $sectionIndex++) {
                    $summaryZoomSection = $summaryZoomCollection->get_Item($sectionIndex);
                    $image = $summaryZoomSection->getZoomImage();
                    if (!isNullJava($image)) {
                        $displayIndex = $sectionIndex + 1;
                        $fileNameBase = $shapeReference->namePart . "_summary_zoom_" . $displayIndex;
                        saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                    }
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从表格形状提取图像

Table 是一种形状。表格中的图像通常以图片填充的形式存储在单元格中。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "table-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, true);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.Table"))) {
                $table = $shapeReference->shape;
                $rowCount = java_values($table->getRows()->size());
                $columnCount = java_values($table->getColumns()->size());
                for ($rowIndex = 0; $rowIndex < $rowCount; $rowIndex++) {
                    for ($columnIndex = 0; $columnIndex < $columnCount; $columnIndex++) {
                        $cell = $table->get_Item($columnIndex, $rowIndex);
                        $fillFormat = $cell->getCellFormat()->getFillFormat();
                        $image = getPictureFillImage($fillFormat);
                        if (!isNullJava($image)) {
                            $displayRow = $rowIndex + 1;
                            $displayColumn = $columnIndex + 1;
                            $fileNameBase = $shapeReference->namePart . "_cell_" . $displayRow . "_" . $displayColumn;
                            saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                        }
                    }
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从图表形状提取图像

Chart 是一种形状。下面的示例从图表区域的图片填充中提取图像。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "chart-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, true);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.Chart"))) {
                $chart = $shapeReference->shape;
                $fillFormat = $chart->getFillFormat();
                $image = getPictureFillImage($fillFormat);
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_chart_area";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

从 SmartArt 形状提取图像

SmartArt 对象是一种形状。根据 SmartArt 布局，图像可能存储在节点项目符号填充中或节点形状的填充格式中。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "smartart-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, true);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.SmartArt"))) {
                $smartArt = $shapeReference->shape;
                $allNodes = $smartArt->getAllNodes();
                $nodeCount = java_values($allNodes->size());
                for ($nodeIndex = 0; $nodeIndex < $nodeCount; $nodeIndex++) {
                    $node = $allNodes->get_Item($nodeIndex);
                    $bulletFillFormat = $node->getBulletFillFormat();
                    $bulletImage = getPictureFillImage($bulletFillFormat);
                    if (!isNullJava($bulletImage)) {
                        $displayNode = $nodeIndex + 1;
                        $fileNameBase = $shapeReference->namePart . "_smartart_node_" . $displayNode . "_bullet";
                        saveOriginalImage($bulletImage, $outputDirectory, $fileNameBase, $savedImageHashes);
                    }

                    $nodeShapes = $node->getShapes();
                    $nodeShapeCount = java_values($nodeShapes->size());
                    for ($nodeShapeIndex = 0; $nodeShapeIndex < $nodeShapeCount; $nodeShapeIndex++) {
                        $nodeShape = $nodeShapes->get_Item($nodeShapeIndex);
                        $fillFormat = $nodeShape->getFillFormat();
                        $image = getPictureFillImage($fillFormat);
                        if (!isNullJava($image)) {
                            $displayNode = $nodeIndex + 1;
                            $displayNodeShape = $nodeShapeIndex + 1;
                            $fileNameBase = $shapeReference->namePart . "_smartart_node_" . $displayNode . "_shape_" . $displayNodeShape;
                            saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                        }
                    }
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

在组合形状中包含图像

组合形状拥有自己的形状集合。共享的 enumerateShapes 辅助方法提供 includeGroupedShapes 选项。当需要检查 GroupShape 对象内部的形状时，将其设为 true。下面的示例从图片框、填充图片的形状、OLE 对象预览、视频帧缩略图和音频帧缩略图中提取图像。若要同时包括表格、图表、SmartArt 和汇总缩放图像，请复用前面章节的专用提取逻辑，并保持相同的递归形状遍历。

use aspose\slides\Presentation;

$inputPath = "sample.pptx";
$outputDirectory = getcwd() . DIRECTORY_SEPARATOR . "all-shape-images";
if (!is_dir($outputDirectory)) {
    mkdir($outputDirectory, 0777, true);
}

$savedImageHashes = [];

$presentation = new Presentation($inputPath);
try {
    $slideCount = java_values($presentation->getSlides()->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $presentation->getSlides()->get_Item($slideIndex);
        $slideNumber = java_values($slide->getSlideNumber());
        $slidePrefix = "slide_" . $slideNumber;
        $shapes = $slide->getShapes();
        $shapeReferences = enumerateShapes($shapes, $slidePrefix, true);
        foreach ($shapeReferences as $shapeReference) {
            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.OleObjectFrame"))) {
                $oleObjectFrame = $shapeReference->shape;
                $image = $oleObjectFrame->getSubstitutePictureFormat()->getPicture()->getImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_ole_preview";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                }

                continue;
            }

            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.VideoFrame"))) {
                $videoFrame = $shapeReference->shape;
                $image = $videoFrame->getPictureFormat()->getPicture()->getImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_video_preview";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                }

                continue;
            }

            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.AudioFrame"))) {
                $audioFrame = $shapeReference->shape;
                $image = $audioFrame->getPictureFormat()->getPicture()->getImage();
                if (!isNullJava($image)) {
                    $fileNameBase = $shapeReference->namePart . "_audio_preview";
                    saveOriginalImage($image, $outputDirectory, $fileNameBase, $savedImageHashes);
                }

                continue;
            }

            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.PictureFrame"))) {
                $pictureFrame = $shapeReference->shape;
                $image = $pictureFrame->getPictureFormat()->getPicture()->getImage();
                saveOriginalImage($image, $outputDirectory, $shapeReference->namePart, $savedImageHashes);
                continue;
            }

            if (java_instanceof($shapeReference->shape, new JavaClass("com.aspose.slides.AutoShape"))) {
                $autoShape = $shapeReference->shape;
                $fillFormat = $autoShape->getFillFormat();
                $image = getPictureFillImage($fillFormat);
                if (!isNullJava($image)) {
                    saveOriginalImage($image, $outputDirectory, $shapeReference->namePart, $savedImageHashes);
                }
            }
        }
    }
} finally {
    $presentation->dispose();
}

边缘情况和实用说明

重复图像： 多个形状可能引用同一图像，或引用字节完全相同的不同图像。如果希望每个唯一图像只输出一次文件，请在写入文件前对 getBinaryData() 的 PPImage 数据进行哈希。
原始数据与转换后输出： 从 getBinaryData() 保存 PPImage 数据可保留嵌入的 JPEG、PNG、GIF、SVG、EMF 或 WMF 数据。使用 getImage() 返回的图像进行保存，则可将输出统一为一致的格式。
不支持的填充类型： 实心、渐变、图案和无填充的形状不包含图片填充。在读取 getPictureFillFormat() 之前，请检查 FillType。
组合形状： 顶层幻灯片形状集合不会将组展平。需要时，请递归检查通过 getShapes() 获得的 GroupShape 内容。
OLE 对象预览： OleObjectFrame 可能通过 getSubstitutePictureFormat() 暴露预览图像，但该图像仅是幻灯片预览，而非 OLE 对象内部的嵌入文件。
视频帧缩略图： VideoFrame 可能通过 getPictureFormat() 暴露预览图像，但该图像仅是幻灯片上显示的海报图，而非从视频流中提取的帧。
音频帧缩略图： AudioFrame 可能通过 getPictureFormat() 暴露图标或缩略图；这并不是嵌入的音频数据。
缩放图像： 幻灯片缩放、节缩放和汇总缩放形状可能通过 getZoomImage() 使用自定义 PPImage 对象。
嵌套形状模型： 表格、图表和 SmartArt 对象实现了 Shape，但它们的图像通常存储在嵌套的表格单元格、图表元素或 SmartArt 节点的格式对象中。
裁剪或变换的图片： 访问 PPImage 可获取存储的图像资源。它不包含形状应用的裁剪、透明度、重新着色、旋转或其他视觉效果的渲染。

常见问题

我能提取原始图像而不受裁剪、效果或形状变换影响吗？

是的。访问 PPImage 对象并将 getBinaryData() 的数据写入磁盘，即可保留演示文稿中存储的原始编码图像，而不是图像在幻灯片上的渲染方式。

我能将所有提取的图像导出为 PNG 吗？

是的。使用 PPImage 及其 getImage() 方法，然后使用 ImageFormat 调用 save()，即可将输出转换为 PNG。这样可能不会保留原始文件类型或矢量数据。

如何避免多次保存相同的图像？

使用 getBinaryData() 的 PPImage 数据的哈希，并将哈希值存入集合中。如果新图像的哈希已存在，则跳过或记录对已有输出文件的另一个引用。

为什么某些形状没有生成图像？

图片框、填充图片的形状、OLE 对象框、媒体框、缩放框、表格、图表和 SmartArt 对象都可能引用图像。某些形状的图像通过嵌套的格式对象暴露，因此单纯检查 getPictureFormat() 或形状的 getFillFormat() 并不总是足够。

我能提取视频帧显示的缩略图吗？

是的。使用 VideoFrame 并读取 getPictureFormat()->getPicture()->getImage()，即可提取随视频帧存储的海报图像，而不是从视频文件生成的帧。

如何确定演示文稿图像集合中的特定图像被哪些形状使用？

Aspose.Slides 并未存储从 PPImage 到形状的反向链接。您需要在遍历过程中构建映射：每当找到图像引用时，记录幻灯片编号、形状路径以及图像哈希或集合项。

我能提取嵌入在 OLE 对象内部的图像，例如附加的文档吗？

您可以从 OleObjectFrame 提取 OLE 对象的幻灯片预览。但该预览并非嵌入的文档本身。若要从嵌入的文件内部提取图像，需要先提取 OLE 数据并使用相应文件类型的工具进行检查。

从演示文稿中获取完整幻灯片背景并保存为图像在幻灯片上调整形状大小