Automatische Größenanpassung von Bildern mit TCPDFAuto-fit images onto current page using TCPDF
Recently I had to fit images onto the current page of a dynamically generated PDF document using the functionality provided by the (superb) TCPDF toolkit.
Due to the fact that I had to include HTML content in the PDFs I was bound to use the writeHTML function. The HTML content was basically structured using plain old <div> containers, that again were seperated into
- text and
sections. The idea was to dynamically add the title and the text content and use the remaining space to auto-fit the image onto the current page, thus not causing a page-break.
Using the functions provided by TCPDF, my idea was to basically calculate the current Y-offset after including the PDF-header, title and text sections and calculate the optimal image height based on the beginning of the footer section.
The following code snippets presents a working prototype. Hereby, $pdf is an instance of TCPDF and the constant MY_PDF_FOOTER_YOFFSET refers to the custom value of the footer height (represented by a negative y-offset).
$pageDimensions = $pdf->getPageDimensions(); $yOffset = ceil($pdf->GetY()); $beginFooter = floor($pageDimensions['hk'] + MY_PDF_FOOTER_YOFFSET - 15); $maxImgHeight = floor($beginFooter - $yOffset);
In case you are wondering about the -15 in the calculation of the beginning of the footer area – I was using an additional image description section right below the image, with a height of (around) 15mm.
Concluding, this functionality can be easily put into a separate function to calculate the optimal (auto-fitting) image size for your (dynamically) generated PDF documents.