Convert PDF to PNG
JPedal provides several methods to allow the rasterization of a PDF file or directory of PDF files into PNG.
PNG is a lossless format that preserves every pixel of the original PDF rendering, including transparency. It is the preferred choice for document archiving, programmatic image processing, or any use case where pixel-perfect quality is required.
JPedal uses JDeli for PNG output. JDeli outperforms standard ImageIO for PNG in benchmarks — it also provides standalone PNG reading and writing.
New to JPedal? Add it to your project first: Maven dependency | Gradle dependency
How do I convert a PDF to PNG from the command line?
JPedal can run as a standalone tool to convert a file or an entire directory in a single command:
java -jar jpedal.jar --convert "inputFileOrFolder" "outputFolder" png
You can also provide additional settings to control the output:
java -jar jpedal.jar --convert "inputFileOrFolder" "outputFolder" png ScalingAsFloat
java -jar jpedal.jar --convert "inputFileOrFolder" "outputFolder" png ScalingAsFloat PageRange
The named variables are:
- ScalingAsFloat: A float value specifying the scaling applied to the output. This is the view scaling divided by 100, for instance 150% becomes 1.5
- PageRange: The range of pages of convert. This follows the same rules as SetOfIntegerSyntax.
This can be a series of comma separated values which are either single page number or range between to values using a dash. For example “1,3,4-7” would give pages 1,3,4,5,6,7
What is the simplest way to convert a PDF to PNG in Java?
The static convenience method converts a whole file or directory in a single call, handling file opening and closing automatically:
ConvertPagesToImages.writeAllPagesAsImagesToDir(
"inputFileOrFolder",
"outputFolder",
"png",
1.33f);
How do I control the PNG output options when converting from PDF in Java?
To configure output settings — such as compression or quality — create a ConvertPagesToImages instance and apply an options object before writing each page:
ConvertPagesToImages convert = new ConvertPagesToImages("inputFile.pdf");
try {
if (convert.openPDFFile()) {
for(int page = 1; page <= convert.getPageCount(); page++) {
final BufferedImage bi = convert.getPageAsImage(page);
final File out = new File("outputFolder" + page + ".png");
// Setters to control output (example with compression)
final PngEncoderOptions options = new PngEncoderOptions();
options.setCompressionFormat(PngCompressionFormat.NONE);
JDeli.write(bi, options, out);
}
}
} catch (PdfException | IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
convert.closePDFfile();
How do I convert specific pages of a PDF to PNG in Java?
Use setPageRange with a PageRanges string before opening the file. The range syntax supports single pages, dash-separated ranges, and comma-separated combinations:
ConvertPagesToImages convert = new ConvertPagesToImages("inputFile.pdf");
// setPageRange gives you the ability to chose the pages you'd like using '-' or ':' for range
// and ',' to move to the next range or you can simply put null for all the pages
convert.setPageRange(new PageRanges("1-5,8:10,15"));
// Above will give us pages 1 to 5(inclusive),8 to 10(inclusive) and 15
try {
if (convert.openPDFFile()) {
convert.getPageRange().forEachRemaining(page -> {
try {
final BufferedImage bi = convert.getPageAsImage(page);
final File out = new File("outputFolder" + page + ".png");
JDeli.write(bi, options, out);
} catch (Exception e) {
e.printStackTrace();
}
});
}
} catch (PdfException e) {
e.printStackTrace();
}
convert.closePDFfile();
How do I create fixed-size PNG thumbnails from a PDF in Java?
The static method accepts a {width, height} array to produce thumbnails at a fixed size:
ConvertPagesToImages.writeAllPagesAsImagesToDir(
"inputFileOrFolder",
"outputFolder",
"png",
new int[] {width, height});
Alternatively, use setFitToSize on a ConvertPagesToImages instance — JPedal preserves the aspect ratio and fits within the given dimensions:
ConvertPagesToImages convert = new ConvertPagesToImages("inputFile.pdf");
//fit with aspect ratio preserved (width will be 300 or height will be 400)
convert.setFitToSize(new int[] {300,400});
try {
if (convert.openPDFFile()) {
for (int page = 1; page <= convert.getPageCount(); page++) {
final BufferedImage bi = convert.getPageAsImage(page);
final File out = new File("outputFolder" + page + ".png");
JDeli.write(bi, OutputFormat.PNG, out);
}
}
} catch (PdfException | IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
convert.closePDFfile();
How do I set the scaling when converting a PDF to PNG in Java?
Use setPageScaling to control the output resolution. A value of 1.33f matches the default 100% view in Acrobat:
ConvertPagesToImages convert = new ConvertPagesToImages("inputFile.pdf");
convert.setPageScaling(1.33f); //which gives same size as Acrobat at 100%
try {
if (convert.openPDFFile()) {
for (int page = 1; page <= convert.getPageCount(); page++) {
final BufferedImage bi = convert.getPageAsImage(page);
final File out = new File("outputFolder" + page + ".png");
JDeli.write(bi, OutputFormat.PNG, out);
}
}
} catch (PdfException | IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
convert.closePDFfile();
How do I convert a password-protected PDF to PNG in Java?
Call setPassword before openPDFFile — the rest of the conversion works identically to an unprotected file:
ConvertPagesToImages convert = new ConvertPagesToImages("inputFile.pdf");
convert.setPassword("password");
try {
if (convert.openPDFFile()) {
for (int page = 1; page <= convert.getPageCount(); page++) {
final BufferedImage bi = convert.getPageAsImage(page);
final File out = new File("outputFolder" + page + ".png");
JDeli.write(bi, OutputFormat.PNG, out);
}
}
} catch (PdfException | IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
convert.closePDFfile();
For the full API see the ConvertPagesToImages and PngEncoderOptions Javadocs. For upscaling or more complex control over the PDF to PNG conversion, ConvertPagesToHiResImages has lots of additional options
We also have a demo project on our GitHub page.
Frequently Asked Questions
Can I convert a whole directory of PDFs to PNG?
Yes. Pass a folder path instead of a file path to any method — JPedal processes all PDFs found in that directory.
Can I convert specific pages of a PDF to PNG?
Yes. Call convert.setPageRange(new PageRanges("1-5,8")) before openPDFFile(). The range syntax supports single pages, dash-separated ranges, and comma-separated combinations.
Can I convert a password-protected PDF to PNG?
Yes. Call convert.setPassword("yourPassword") before openPDFFile().
How do I control the output resolution or DPI?
Use convert.setPageScaling(1.33f) — 1.33f matches Acrobat’s 100% view. For fixed pixel dimensions use convert.setFitToSize(new int[]{width, height}) instead.
Does JPedal require any third-party dependencies?
No. JPedal is a self-contained Java library with no third-party runtime dependencies.