Merge pull request #1607 from syncfusion-content/988484-LinuxUG

988484-Add FAQ about using Linux in XlsIO

Author: Mohan2401

Document-Processing/Excel/Excel-Library/NET/Linux.md

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+---
+title: FAQ about using XlsIO in Linux | Syncfusion
+description: This page explains about the frequently asked questions about using the .NET Excel (XlsIO) library in Linux environment.
+platform: document-processing
+control: XlsIO
+documentation: UG
+---
+
+# Frequently asked questions about using XlsIO in Linux
+
+The frequently asked questions about using XlsIO in Linux environment are listed below.
+
+## How to copy necessary fonts to Linux containers?
+
+Excel to PDF conversion on Linux relies on system fonts available inside the container. By default, only a limited set is installed. Copy the required fonts to "/usr/local/share/fonts/" before conversion. Refer to the steps below to copy fonts.
+
+**Steps:**
+
+Step 1: Create a **Fonts** folder inside your project (or next to the solution).
+Step 2: Place the required TrueType/OpenType font files (.ttf/.otf) in that folder.
+Step 3: Add the following to your Dockerfile to copy the fonts to the container.
+
+{% tabs %}
+
+{% highlight Dockerfile %}
+
+COPY ["ProjectName/Fonts/*.*", "/usr/local/share/fonts/"]
+
+{% endhighlight %}     
+
+{% endtabs %}   
+
+You can download a complete working sample from <a href="https://github.com/SyncfusionExamples/XlsIO-Examples/tree/master/Linux/Copy%20fonts%20to%20linux%20containers/.NET/Copy_fonts_to_linux_containers">GitHub</a>.
+
+## How to install Microsoft compatible fonts on Linux?
+
+By default, Linux systems include a limited set of fonts located at "/usr/share/fonts/". For document conversion scenarios that require Microsoft-compatible fonts, you can install them using the following command:
+
+{% tabs %}
+
+{% highlight Kconfig %}
+sudo apt-get install ttf-mscorefonts-installer
+{% endhighlight %}
+
+{% endtabs %}
+
+After installation, the fonts will be available at "/usr/share/fonts/truetype/msttcorefonts", and will be used during conversion.
+
+N> Ensure you have obtained the appropriate license clearance from Microsoft before using these fonts in your environment.
+
+## How to install necessary fonts in Linux containers?
+
+In Excel to PDF conversion, Essential<sup>&reg;</sup> XlsIO uses the fonts installed in the production environment to measure and render text. If a required font is missing, an alternate font will be used based on the environment, which may affect layout fidelity.
+
+To ensure proper font preservation, install all fonts used in the Excel document within the container.
+
+Use the following code snippet to install fonts in containers.
+
+{% tabs %}
+
+{% highlight Dockerfile %}
+RUN apt-get update -y && \
+    apt-get install -y fontconfig debconf && \
+    echo "ttf-mscorefonts-installer msttcorefonts/accepted-mscorefonts-eula select true" | debconf-set-selections && \
+    apt-get install -y \
+        fonts-arphic-ukai \
+        fonts-arphic-uming \
+        fonts-ipafont-mincho \
+        fonts-ipafont-gothic \
+        fonts-unfonts-core \
+        ttf-wqy-zenhei \
+        ttf-mscorefonts-installer && \
+    fc-cache -fv && \
+    apt-get clean && \
+    apt-get autoremove -y && \
+    rm -rf /var/lib/apt/lists/*
+{% endhighlight %}
+
+{% endtabs %}
+
+If font preservation issues persist after installing the required packages, you can manually copy the necessary font files into the container.
+
+## How to set culture/locale in Docker containers (Windows and Linux)?
+ 
+By default, Culture/Locale that is specified in the container image will be used in Docker containers.
+
+If you want to change or set Culture/Locale in the Docker container, set the required Culture/Locale in Docker file.
+
+T> We recommend you check whether the required Culture/Locale is set to the Docker containers since some Docker container may not have Culture/Locale.
+
+The following code example will set en_US locale to the container by setting Language to en_US.
+
+{% tabs %}
+
+{% highlight Dockerfile %}
+ENV LANG="en_US.UTF-8"
+{% endhighlight %}
+
+{% endtabs %}
+
+## How to resolve LibSkiaSharp not found exception?
+
+This exception occurs when required native dependencies are missing. Ensure the necessary packages are installed by adding this to your Docker file:
+
+{% tabs %}
+
+{% highlight Dockerfile %}
+RUN apt-get update -y && apt-get install libfontconfig -y
+{% endhighlight %}
+
+{% endtabs %}
+
+In production environment (hosted server machine), ensure whether the Visual C++ Redistributable is properly installed.
+
+[Download](https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170) and install Visual C++, if not installed.