BU is a simple app which adds bitmap images over any .pdf file. Primary usage - adding a facsimile, a picture of a handwritten autograph or a print of a rubber stamp onto some kind of document. The app is made for lazy ppl, who have to sign many documents a day and tired of printing and scanning their documents and forms. In other words this app saves trees, cuts emissions, protects environment, etc.
As a side-feature, BitteUnterschreiben is capable of merging multiple .pdf files, extracting and reordering pages.
BU has a blending mode option ('Darken' or 'Multiply' or 'No-op') for overlaying images and size/quality settings (select target dpi and jpg compression).
BU relies upon Apache PDFBox 2, an open-source PDF library in terms of rendering and saving. Other technologies used: Logback for logging, Jackson for .yml processing, JUnit+Mockito for testing and Lombok for anything else.
Current version requires user to use .png, .jpg, .tif, .bmp files as overlay images. Images are treated as scanned in 300 dpi; transparency is desirable but not required (please see the examples in 'PNG' directory).
BU features two-language localization: in Russian and bad English.
Placing overlays on page
Blended images as final .pdf file