Issue #18 - Allow to define the screen resolution as an environment variable

Author: ppodgorsek

Dockerfile

@@ -6,6 +6,10 @@ LABEL description Robot Framework in Docker.
 VOLUME /opt/robotframework/reports
 VOLUME /opt/robotframework/tests
 
+ENV SCREEN_COLOUR_DEPTH 24
+ENV SCREEN_HEIGHT 1080
+ENV SCREEN_WIDTH 1920
+
 RUN dnf upgrade -y\
 	&& dnf install -y\
 		chromedriver-61.0.3163.100-1.fc26\
@@ -30,5 +34,4 @@ RUN mv /usr/lib64/chromium-browser/chromium-browser /usr/lib64/chromium-browser/
 
 ENV PATH=/opt/robotframework/bin:/opt/robotframework/drivers:$PATH
 
-ENTRYPOINT ["xvfb-run", "--server-args=-screen 0 1920x1080x24 -ac", "robot", "--outputDir", "/opt/robotframework/reports", "/opt/robotframework/tests"]
-
+ENTRYPOINT ["xvfb-run", "--server-args=-screen 0 ${SCREEN_HEIGHT}x${SCREEN_WIDTH}x${SCREEN_COLOUR_DEPTH} -ac", "robot", "--outputDir", "/opt/robotframework/reports", "/opt/robotframework/tests"]

README.md

@@ -17,8 +17,8 @@ The versions used in the latest version are:
 
 * Robot Framework 3.0.2
 * Robot Framework selenium2library 1.8.0
-* Firefox 55.0
-* Chromium 60.0
+* Firefox 57.0
+* Chromium 61.0
 
 ## Running the container
 
@@ -33,3 +33,11 @@ This container can be run using the following command:
 Browsers can be easily switched. It is recommended to define `${BROWSER} %{BROWSER}` in your Robot variables and to use `${BROWSER}` in your test cases. This allows to set the browser in a single place if needed.
 
 When running your tests, simply add `-e BROWSER=chrome` or `-e BROWSER=firefox` to the run command.
+
+### Changing the container screen's resolution
+
+It is possible to define the settings of the virtual screen in which the browser is run by changing several environment variables:
+
+* `SCREEN_COLOUR_DEPTH` (default: 24)
+* `SCREEN_HEIGHT` (default: 1080)
+* `SCREEN_WIDTH` (default: 1920)