Add 'make htmlview' to open index page

Makefile

@@ -21,6 +21,11 @@ doc html:
 	python3 -c "import PIL" > /dev/null 2>&1 || python3 -m pip install .
 	$(MAKE) -C docs html
 
+.PHONY: htmlview
+htmlview:
+	python3 -c "import PIL" > /dev/null 2>&1 || python3 -m pip install .
+	$(MAKE) -C docs htmlview
+
 .PHONY: doccheck
 doccheck:
 	$(MAKE) doc
@@ -40,6 +45,7 @@ help:
 	@echo "  doc                make HTML docs"
 	@echo "  docserve           run an HTTP server on the docs directory"
 	@echo "  html               to make standalone HTML files"
+	@echo "  htmlview           to open the index page built by the html target in your browser"
 	@echo "  inplace            make inplace extension"
 	@echo "  install            make and install"
 	@echo "  install-coverage   make and install with C coverage"

docs/Makefile

@@ -19,6 +19,7 @@ I18NSPHINXOPTS  = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
 help:
 	@echo "Please use \`make <target>' where <target> is one of"
 	@echo "  html       to make standalone HTML files"
+	@echo "  htmlview   to open the index page built by the html target in your browser"
 	@echo "  serve      to start a local server for viewing docs"
 	@echo "  livehtml   to start a local server for viewing docs and auto-reload on change"
 	@echo "  dirhtml    to make HTML files named index.html in directories"
@@ -196,6 +197,10 @@ doctest:
 	@echo "Testing of doctests in the sources finished, look at the " \
 	      "results in $(BUILDDIR)/doctest/output.txt."
 
+.PHONY: htmlview
+htmlview: html
+	$(PYTHON) -c "import os, webbrowser; webbrowser.open('file://' + os.path.realpath('$(BUILDDIR)/html/index.html'))"
+
 .PHONY: livehtml
 livehtml: html
 	livereload $(BUILDDIR)/html -p 33233

docs/make.bat

@@ -19,6 +19,7 @@ if "%1" == "help" (
 	:help
 	echo.Please use `make ^<target^>` where ^<target^> is one of
 	echo.  html       to make standalone HTML files
+	echo.  htmlview   to open the index page built by the html target in your browser
 	echo.  dirhtml    to make HTML files named index.html in directories
 	echo.  singlehtml to make a single large HTML file
 	echo.  pickle     to make pickle files
@@ -52,6 +53,17 @@ if "%1" == "html" (
 	goto end
 )
 
+if "%1" == "htmlview" (
+    cmd /C %this% html
+
+    if EXIST "%BUILDDIR%\html\index.html" (
+        echo.Opening "%BUILDDIR%\html\index.html" in the default web browser...
+        start "" "%BUILDDIR%\html\index.html"
+    )
+
+    goto end
+)
+
 if "%1" == "dirhtml" (
 	%SPHINXBUILD% -b dirhtml %ALLSPHINXOPTS% %BUILDDIR%/dirhtml
 	if errorlevel 1 exit /b 1