Working with Images

Select images at document or page scope, by collection or coordinates. Singular selectors return the language's empty-result type; plural selectors return a collection.

Complete image-replacement workflow

Download images.pdf as input.pdf and replacement-logo.png into the same directory. The program replaces the first image and saves output.pdf.

Python

from pathlib import Path
from pdfdancer import PDFDancer

with PDFDancer.open(Path("input.pdf")) as pdf:
    images = pdf.select_images()
    if not images:
        raise RuntimeError("The sample image was not found")
    result = images[0].replace_from_file(Path("replacement-logo.png"))
    if not result.success:
        raise RuntimeError(result.message)
    pdf.save("output.pdf")

TypeScript

import * as fs from 'node:fs';
import {PDFDancer} from 'pdfdancer-client-typescript';

const input = new Uint8Array(fs.readFileSync('input.pdf'));
const pdf = await PDFDancer.open(input);
const images = await pdf.selectImages();
if (images.length === 0) throw new Error('The sample image was not found');
const result = await images[0].replaceFromFile('replacement-logo.png');
if (!result.success) throw new Error(result.message ?? 'Image replacement failed');
await pdf.save('output.pdf');

Java

import com.pdfdancer.client.rest.PDFDancer;
import java.io.File;

public class ReplaceImage {
    public static void main(String[] args) throws Exception {
        PDFDancer pdf = PDFDancer.createSession("input.pdf");
        var images = pdf.selectImages();
        if (images.isEmpty()) throw new IllegalStateException("The sample image was not found");
        var result = images.get(0).replace(new File("replacement-logo.png"));
        if (!result.success()) throw new IllegalStateException(result.message());
        pdf.save("output.pdf");
    }
}

Open output.pdf and confirm that the original image was replaced. The remaining examples assume an open pdf session.

Select and inspect images

Python

all_images = pdf.select_images()
page_images = pdf.page(1).select_images()
near_point = pdf.page(1).select_images_at(72, 700, tolerance=1.0)
image = pdf.page(1).select_image_at(72, 700, tolerance=1.0)
if image is not None:
    print(image.width, image.height, image.aspect_ratio, image.page_number)

TypeScript

const allImages = await pdf.selectImages();
const pageImages = await pdf.page(1).selectImages();
const nearPoint = await pdf.page(1).selectImagesAt(72, 700, 1.0);
const image = await pdf.page(1).selectImageAt(72, 700, 1.0);
if (image) console.log(image.width, image.height, image.aspectRatio, image.position.pageNumber);

Java

var allImages = pdf.selectImages();
var pageImages = pdf.page(1).selectImages();
var nearPoint = pdf.page(1).selectImagesAt(72, 700, 1.0);
var image = pdf.page(1).selectImageAt(72, 700, 1.0);
image.ifPresent(value -> System.out.println(
        value.getWidth() + " × " + value.getHeight()
                + ", ratio=" + value.getAspectRatio()));

Add images

Use the image builder at document scope with an explicit one-based page, or use a page-scoped builder. Supply an image file and PDF coordinates before calling the terminal add operation.

Python

from pathlib import Path

if not pdf.new_image().from_file(Path("logo.png")).at(1, 72, 700).add():
    raise RuntimeError("Document-scoped image add failed")
if not pdf.page(2).new_image().from_file(Path("seal.png")).at(72, 80).add():
    raise RuntimeError("Page-scoped image add failed")

TypeScript

if (!await pdf.newImage().fromFile('logo.png').at(1, 72, 700).add()) {
  throw new Error('Document-scoped image add failed');
}
if (!await pdf.page(2).newImage().fromFile('seal.png').at(72, 80).add()) {
  throw new Error('Page-scoped image add failed');
}

Java

import java.io.File;

if (!pdf.newImage().fromFile(new File("logo.png")).at(1, 72, 700).add()) {
    throw new IllegalStateException("Document-scoped image add failed");
}
if (!pdf.page(2).newImage().fromFile(new File("seal.png")).at(72, 80).add()) {
    throw new IllegalStateException("Page-scoped image add failed");
}

Transformation methods return CommandResult; check success, message, warning, and the affected element identifier. Positive image rotation angles are clockwise.

Replace an image

Replacement keeps the selected image object's placement while changing its image data.

Python

from pathlib import Path

image = pdf.page(1).select_image_at(72, 700, tolerance=1.0)
if image is None:
    raise RuntimeError("Image not found")
result = image.replace_from_file(Path("new-logo.png"))
if not result.success:
    raise RuntimeError(result.message)

TypeScript

const image = await pdf.page(1).selectImageAt(72, 700, 1.0);
if (!image) throw new Error('Image not found');
const result = await image.replaceFromFile('new-logo.png');
if (!result.success) throw new Error(result.message ?? 'Replacement failed');

Java

import java.io.File;

var image = pdf.page(1).selectImageAt(72, 700, 1.0)
        .orElseThrow(() -> new IllegalStateException("Image not found"));
var result = image.replace(new File("new-logo.png"));
if (!result.success()) throw new IllegalStateException(result.message());

Scale, rotate, and move

Choose one transformation, check its result, then select the image again before calculations that depend on current bounds.

Python

# Scale by a factor.
result = image.scale(0.5)

# Or scale to a box in PDF points.
result = image.scale_to(180, 60, preserve_aspect_ratio=True)

# Or rotate clockwise and move to new PDF coordinates.
result = image.rotate(90)
moved = image.move_to(144, 650)

if not result.success or not moved:
    raise RuntimeError(result.message)

TypeScript

// Scale by a factor.
let result = await image.scale(0.5);

// Or scale to a box in PDF points.
result = await image.scaleTo(180, 60, true);

// Or rotate clockwise and move to new PDF coordinates.
result = await image.rotate(90);
const moved = await image.moveTo(144, 650);

if (!result.success || !moved) throw new Error(result.message ?? 'Transform failed');

Java

// Scale by a factor.
var result = image.scale(0.5);

// Or scale to a box in PDF points.
result = image.scaleTo(180, 60, true);

// Or rotate clockwise and move to new PDF coordinates.
result = image.rotate(90);
boolean moved = image.moveTo(144, 650);

if (!result.success() || !moved) {
    throw new IllegalStateException(result.message());
}

The alternatives above illustrate individual methods; do not apply all of them in sequence unless that combined transformation is intended.

Crop, opacity, flipping, and pixel-region fill

Crop and fill-region dimensions are image pixels, not PDF page points. Opacity ranges from 0.0 (transparent) to 1.0 (opaque).

Python

from pdfdancer import Color

crop_result = image.crop(left=10, top=5, right=10, bottom=5)
opacity_result = image.set_opacity(0.75)
flip_result = image.flip_horizontal()
fill_result = image.fill_region(0, 0, 40, 20, Color(255, 255, 255))

for result in (crop_result, opacity_result, flip_result, fill_result):
    if not result.success:
        raise RuntimeError(result.message)

TypeScript

import {Color} from 'pdfdancer-client-typescript';

const cropResult = await image.crop(10, 5, 10, 5);
const opacityResult = await image.setOpacity(0.75);
const flipResult = await image.flipHorizontal();
const fillResult = await image.fillRegion(0, 0, 40, 20, new Color(255, 255, 255));

for (const result of [cropResult, opacityResult, flipResult, fillResult]) {
  if (!result.success) throw new Error(result.message ?? 'Image transform failed');
}

Java

import com.pdfdancer.common.model.Color;

var cropResult = image.crop(10, 5, 10, 5);
var opacityResult = image.opacity(0.75);
var flipResult = image.flipHorizontal();
var fillResult = image.fillRegion(0, 0, 40, 20, new Color(255, 255, 255));

for (var result : java.util.List.of(
        cropResult, opacityResult, flipResult, fillResult)) {
    if (!result.success()) throw new IllegalStateException(result.message());
}

These calls are shown together to document their parameters. For production edits, select the image again between transformations when current dimensions or coordinates influence the next operation.

Clipping

An image can remain visually clipped after moving because its clipping path is an independent PDF graphics-state constraint. Use clearClipping only when removing that constraint is intended, then inspect the rendered output.

Python

if not image.clear_clipping():
    raise RuntimeError("Image clipping could not be cleared")

TypeScript

if (!await image.clearClipping()) throw new Error('Image clipping could not be cleared');

Java

if (!image.clearClipping()) {
    throw new IllegalStateException("Image clipping could not be cleared");
}

Deletion

Delete the selected typed image rather than relying on its previous coordinates after other transformations. Re-run the selector if the workflow may have changed its identity or position.

Python

if not image.delete():
    raise RuntimeError("Image deletion failed")

TypeScript

if (!await image.delete()) throw new Error('Image deletion failed');

Java

if (!image.delete()) throw new IllegalStateException("Image deletion failed");