The best of two worlds.
The comparison of circuit diagrams and technical drawings is a
special challenge for a digital PDF comparison: Other software
solutions are either optimized to compare graphics or to
compare text. For your application, however, you need both.
What is a graphical PDF comparison?
In the case of a graphical PDF comparison, the two documents
are first transferred to pixel images using a PDF
renderer. Then, a digital image comparison takes
place. Deviations are highlighted as pixels or groups of
pixels. Text and vector drawings are also compared pixel-based
as part of the entire image.
Advantages: Even the smallest deviations up to individual
pixels can be detected. The comparison includes all visible
contents of the PDF (raster images, vector graphics, text).
Disadvantages: Text may not change in content, position or
presentation. This means changed line or page breaks, small
differences in font kerning, or changed fonts lead to large
pixel deviations so that actual deviations are difficult to
distinguish from artifacts.
What is a text-based PDF comparison?
In a text-based PDF comparison, the text is first extracted
from the documents. Then a digital text comparison takes
place. Deviations are displayed as words or letters.
Advantages: The text can be compared for content
differences, even if the layout of the text differs greatly
in both documents. For example, changed positions, line
breaks or different fonts are not a problem for the
comparison.
Disadvantages: The comparison only includes text visible
for full-text search. Other PDF content such as raster
images and vector graphics are not compared. Even text that
has been converted into paths, or text from scans is not
compared by default.
The special feature of Diff GT: the ingenious combination of graphics and text comparison
Diff GT considers the text content in your PDFs using
algorithms for text comparison and the graphic part in your
PDFs with algorithms for pixel-accurate image comparison.
This combination gives you all the advantages of both
approaches and you bypass the previously inevitable
disadvantages. Diff GT can thus achieve perfect comparison
results: text is compared very tolerantly to layout changes at
the content level, and at the same time all graphical elements
are compared with digital precision for visual differences.
Did you already know …
…that the abbreviation GT in Diff GT stands for graphics and
text and at the same time in the automotive industry for Gran
Turismo: loosely translates to “great ride” with high comfort
and sporty engine - two aspects that also fit well with the
design goals of Diff GT.