Adventures with Skia, WASM and a JS API for Pathkit

See shell.html::entrypoint() for the JS side of things.

See wasm_main.cpp for the C++ side of things
(EMSCRIPTEN_BINDINGS at the bottom is what glues the two parts
together - in general the strings are for JS and the not strings
are the C++)

To build this yourself, follow the getting started instructions:
https://kripken.github.io/emscripten-site/docs/getting_started/downloads.html

and download this patch.  Then, update compile.sh to point at your
sdk and run it (e.g. $SKIA_ROOT/experimental/wasm/compile.sh)

Then navigate a browser (e.g. Chrome) to
http://localhost:8000/out/wasm/pathkit.html

So far, can compile with compile.sh, but not really with
GN/ninja (the compilation into many object files and a link
at the end seems to mess emscripten up)


Bug: skia:
Change-Id: If6b300e2b102469e17841265c7866f1a81094d70
Reviewed-on: https://skia-review.googlesource.com/137422
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/experimental/wasm/compile.sh b/experimental/wasm/compile.sh
new file mode 100755
index 0000000000..d2e7098a0b
--- /dev/null
+++ b/experimental/wasm/compile.sh
@@ -0,0 +1,72 @@
+#!/bin/bash
+# Copyright 2018 Google LLC
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+# Run this from $SKIA_HOME, not from the directory this file is in.
+# This expects the environment variable EMSDK to be set
+HTML_SHELL="./experimental/wasm/shell.html"
+
+if [[ ! -d $EMSDK ]]; then
+    echo "Be sure to set the EMSDK environment variable."
+    exit 1
+fi
+
+source $EMSDK/emsdk_env.sh
+
+echo "Compiling"
+
+set -e
+
+mkdir -p out/wasm
+
+# Use -O0 for larger builds (but generally quicker)
+# Use -Oz for (much slower, but smaller/faster) production builds
+em++ -Oz -std=c++14 \
+-Iinclude/config \
+-Iinclude/core \
+-Iinclude/private \
+-Iinclude/pathops \
+-Iinclude/utils \
+-Isrc/core \
+--bind \
+-s WASM=1 \
+-s NO_EXIT_RUNTIME=1 \
+-s ERROR_ON_UNDEFINED_SYMBOLS=1 \
+-s ERROR_ON_MISSING_LIBRARIES=1 \
+--shell-file $HTML_SHELL \
+-o out/wasm/pathkit.html \
+experimental/wasm/wasm_main.cpp \
+src/core/SkArenaAlloc.cpp \
+src/core/SkGeometry.cpp \
+src/core/SkMallocPixelRef.cpp \
+src/core/SkMath.cpp \
+src/core/SkMatrix.cpp \
+src/core/SkPath.cpp \
+src/core/SkPathRef.cpp \
+src/core/SkPoint.cpp \
+src/core/SkRect.cpp \
+src/core/SkStream.cpp \
+src/core/SkString.cpp \
+src/core/SkStringUtils.cpp \
+src/core/SkUtils.cpp \
+src/pathops/*.cpp \
+src/ports/SkDebug_stdio.cpp \
+src/ports/SkMemory_malloc.cpp \
+src/utils/SkParse.cpp \
+src/utils/SkParsePath.cpp
+
+# Add the following for debugging (bloats production code size otherwise)
+# list of all (most?) settings: https://github.com/kripken/emscripten/blob/incoming/src/settings.js
+#-s ASSERTIONS=1 \
+#-s DEMANGLE_SUPPORT=1 \
+#-g2
+
+# To build with ASM.js (instead of WASM)
+# This doesn't give the same results as native c++ or wasm....
+#-s WASM=0 \
+#-s ALLOW_MEMORY_GROWTH=1 \
+
+python -m SimpleHTTPServer 8000