[Tex/LaTex] PDF text becomes blurry when \includegraphics is used, why?

graphicsxetex

I'm compiling this code with XeLaTeX:

\documentclass[11pt]{article}
\usepackage{graphicx}
\begin{document}
    This text is blurry if there is an image.
    \includegraphics{Test.png}
\end{document}

where the image I'm including is:

If I comment out the \includesgraphics, I get:

Clear

If I don't, I get:

Blurry

Why does the text look different (in my eyes, blurrier) when there is an image on the screen?
How can I prevent this from happening in XeLaTeX?

Best Answer

There is no need to use a bitmap image for the symbol. It is the Unicode character ☆:

U+2606 WHITE STAR

LuaTeX

Even with bold fonts, the symbol does not have the thickness of the lines usually. This can be manipulated by package pdfrender that works for pdfTeX/LuaTeX in PDF mode. Example:

\documentclass{article}
\usepackage{fontspec}
\usepackage{pdfrender}

\newcommand*{\mysymbfont}{%
  \fontspec{\myfont}%
  \fontsize{5em}{5em}\selectfont
}
\newcommand*{\textbigwhitestar}{^^^^2606}

\begin{document}
  \tabcolsep=.2\tabcolsep
  \begin{tabular}{llll}
    \xdef\myfont{DejaVuSans-Bold.ttf}%
      \texttt{\myfont}:
    &
      \mysymbfont
      \textbigwhitestar
    & \mysymbfont
      \textpdfrender{
        TextRenderingMode=Stroke,
        LineJoinStyle=Round,
        LineWidth=.5pt,
      }{\textbigwhitestar}
    & \mysymbfont
      \textpdfrender{
        TextRenderingMode=FillStroke,
        LineJoinStyle=Round,
        LineWidth=2pt,
      }{\textbigwhitestar}
    \\
    \xdef\myfont{xits-math.otf}%
      \texttt{\myfont}:
    & \mysymbfont
      \textbigwhitestar
    & \mysymbfont
      \textpdfrender{
        TextRenderingMode=Stroke,
        LineJoinStyle=Round,
        LineWidth=.5pt,
      }{\textbigwhitestar}
    & \mysymbfont
      \textpdfrender{
        TextRenderingMode=FillStroke,
        LineJoinStyle=Round,
        LineWidth=1pt,
      }{\textbigwhitestar}
  \end{tabular}
\end{document}

XeTeX

In XeTeX the symbol can be included as PDF file, generated via LuaTeX, e.g.:

% whitestar-raw.tex for LuaLaTeX
\documentclass{article}
\usepackage{fontspec}
\usepackage{pdfrender}
\pagestyle{empty}

\begin{document}
  \fontspec{DejaVuSans-Bold.ttf}
  \fontsize{5em}{5em}\selectfont
  \textpdfrender{
    TextRenderingMode=FillStroke,
    LineJoinStyle=Round,
    LineWidth=2pt,
  }{^^^^2606}
\end{document}

Then compile it and crop the margins:

lualatex whitestar-raw
pdfcrop whitestar-raw.pdf whitestar.pdf

In XeTeX the PDF file is included via:

\includegraphics{whitestar}

Related Solutions

PDF Graphics – Fix Blurry PNG in PDF

A 94dpi PNG figure included in a PDF file will certainly look blurry on screen.

Most likely your PDF viewer doesn't show your document so that 1 pixel in the PNG file corresponds to 1 pixel on screen. Even if you manage to find exactly the right zoom level, the origin of the PNG file is not necessarily aligned with screen pixels. Some kind of interpolation is done in virtually any situation if you have PNG (or JPEG) figures in PDF files.

How to do it correctly:

Use vector graphics for line drawings.
Use high-resolution JPEG files for photos. Something like 300 dpi is usually enough; looks good on screen and when printed. There is always some scaling and interpolation involved when displayed on screen, but in practice you don't really see any softness in photos.
If you have a line drawing and if you really must use raster files instead of vector graphics, then use very high-resolution PNG files. Something like 600 dpi is usually enough. It looks good when printed. It will look reasonably good on screen; there will be some softness, e.g. horizontal and vertical lines are not as sharp as you would like, but you can usually live with this solution fairly well.

fonts,graphics,pdftex,color – Resolve Conflict Between Color, Graphicx, and Libertine

These option clashes happen when a package is requested to be loaded on two different positions, like by you and inside another package, but with different options. The package is loaded by the first \usepackage (or its twin \RequirePackage); it isn't loaded again when it is requested again. It simply can't be loaded a second time. Therefore the new options can be activated and previous options might conflict with the second usage. So LaTeX creates an error to report this issue to you.

The way to fix this is to declare the options beforehand using \PassOptionsToPackage{<options>}{<package>}. Then they are used wherever the package is loaded.

\documentclass{article}
\usepackage{ifpdf}
\ifpdf
    \PassOptionsToPackage{pdftex,usenames,dvipsnames}{color}
    \usepackage[T1]{fontenc}
    \usepackage{libertine} % most likely loads 'color' itself
    %\usepackage{lmodern} % doesn't load 'color'
    \usepackage{color}
    \usepackage[pdftex]{graphicx}
\else
    %\bye
\fi
\begin{document}
Hello, world!
\end{document}

I can't test it by myself, because I don't have the libertine package installed.

PS:

I don't think you need to set pdftex manually. Normally packages do a good job recognizing the driver by themselves. Also you might want to use the extended xcolor package instead of color.