FM, a dumber new testing tool

FM's a bit like DM, and a bit like the old GM tool, maybe closer to GM.

FM always does one serial run through of a list of GM, image, or .skp
sources (-s/--sources) into one drawing configuration, set at a high
level with -b/--backend, fine-tuned by flags like --ct, --at, --gamut,
--samples, etc.

FM prints all available GMs when run with no arguments, part of
how it integrates well with external parallelization like xargs:

   out/fm | time xargs -n4 -P32 out/fm -b cpu ... -s
   out/fm | time xargs -n32 -P8 out/fm -b gl ... -s
   ls *.skp | xargs ... out/fm ... -s
   ...

TODO later:
   vector backends: --backend pdf, svg, xps, skp
   --source *.svg, *.json (Skottie)
   Create/update a dm.json file

Change-Id: Idacbd2785deaf6f1d33674c66c4d984fa91dbd85
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/203520
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/tools/HashAndEncode.cpp b/tools/HashAndEncode.cpp
new file mode 100644
index 0000000..91814fc
--- /dev/null
+++ b/tools/HashAndEncode.cpp
@@ -0,0 +1,160 @@
+// Copyright 2019 Google LLC.
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+#include "HashAndEncode.h"
+#include "SkICC.h"
+#include "SkString.h"
+#include "png.h"
+
+static constexpr skcms_TransferFunction k2020_TF =
+    {2.22222f, 0.909672f, 0.0903276f, 0.222222f, 0.0812429f, 0, 0};
+
+static sk_sp<SkColorSpace> rec2020() {
+    return SkColorSpace::MakeRGB(k2020_TF, SkNamedGamut::kRec2020);
+}
+
+HashAndEncode::HashAndEncode(const SkBitmap& bitmap) : fSize(bitmap.info().dimensions()) {
+    skcms_AlphaFormat srcAlpha;
+    switch (bitmap.alphaType()) {
+        case kUnknown_SkAlphaType: SkASSERT(false); return;
+
+        case kOpaque_SkAlphaType:
+        case kUnpremul_SkAlphaType: srcAlpha = skcms_AlphaFormat_Unpremul;        break;
+        case kPremul_SkAlphaType:   srcAlpha = skcms_AlphaFormat_PremulAsEncoded; break;
+    }
+
+    skcms_PixelFormat srcFmt;
+    switch (bitmap.colorType()) {
+        case kUnknown_SkColorType: SkASSERT(false); return;
+
+        case kAlpha_8_SkColorType:      srcFmt = skcms_PixelFormat_A_8;          break;
+        case kRGB_565_SkColorType:      srcFmt = skcms_PixelFormat_BGR_565;      break;
+        case kARGB_4444_SkColorType:    srcFmt = skcms_PixelFormat_ABGR_4444;    break;
+        case kRGBA_8888_SkColorType:    srcFmt = skcms_PixelFormat_RGBA_8888;    break;
+        case kBGRA_8888_SkColorType:    srcFmt = skcms_PixelFormat_BGRA_8888;    break;
+        case kRGBA_1010102_SkColorType: srcFmt = skcms_PixelFormat_RGBA_1010102; break;
+        case kGray_8_SkColorType:       srcFmt = skcms_PixelFormat_G_8;          break;
+        case kRGBA_F16Norm_SkColorType: srcFmt = skcms_PixelFormat_RGBA_hhhh;    break;
+        case kRGBA_F16_SkColorType:     srcFmt = skcms_PixelFormat_RGBA_hhhh;    break;
+        case kRGBA_F32_SkColorType:     srcFmt = skcms_PixelFormat_RGBA_ffff;    break;
+
+        case kRGB_888x_SkColorType:     srcFmt = skcms_PixelFormat_RGBA_8888;
+                                        srcAlpha = skcms_AlphaFormat_Opaque;       break;
+        case kRGB_101010x_SkColorType:  srcFmt = skcms_PixelFormat_RGBA_1010102;
+                                        srcAlpha = skcms_AlphaFormat_Opaque;       break;
+    }
+
+    skcms_ICCProfile srcProfile = *skcms_sRGB_profile();
+    if (auto cs = bitmap.colorSpace()) {
+        cs->toProfile(&srcProfile);
+    }
+
+    // Our common format that can represent anything we draw and encode as a PNG:
+    //   - 16-bit big-endian RGBA
+    //   - unpremul
+    //   - Rec. 2020 gamut and transfer function
+    skcms_PixelFormat dstFmt   = skcms_PixelFormat_RGBA_16161616BE;
+    skcms_AlphaFormat dstAlpha = skcms_AlphaFormat_Unpremul;
+    skcms_ICCProfile dstProfile;
+    rec2020()->toProfile(&dstProfile);
+
+    int N = fSize.width() * fSize.height();
+    fPixels.reset(new uint64_t[N]);
+
+    if (!skcms_Transform(bitmap.getPixels(), srcFmt, srcAlpha, &srcProfile,
+                         fPixels.get(),      dstFmt, dstAlpha, &dstProfile, N)) {
+        SkASSERT(false);
+        fPixels.reset(nullptr);
+    }
+}
+
+void HashAndEncode::write(SkWStream* st) const {
+    st->write(&fSize, sizeof(fSize));
+    if (const uint64_t* px = fPixels.get()) {
+        st->write(px, sizeof(*px) * fSize.width() * fSize.height());
+    }
+
+    // N.B. changing salt will change the hash of all images produced by DM,
+    // and will cause tens of thousands of new images to be uploaded to Gold.
+    int salt = 1;
+    st->write(&salt, sizeof(salt));
+}
+
+bool HashAndEncode::writePngTo(const char* path,
+                               const char* md5,
+                               CommandLineFlags::StringArray key,
+                               CommandLineFlags::StringArray properties) const {
+    if (!fPixels) {
+        return false;
+    }
+
+    FILE* f = fopen(path, "wb");
+    if (!f) {
+        return false;
+    }
+
+    png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
+    if (!png) {
+        fclose(f);
+        return false;
+    }
+
+    png_infop info = png_create_info_struct(png);
+    if (!info) {
+        png_destroy_write_struct(&png, &info);
+        fclose(f);
+        return false;
+    }
+
+    SkString description;
+    description.append("Key: ");
+    for (int i = 0; i < key.count(); i++) {
+        description.appendf("%s ", key[i]);
+    }
+    description.append("Properties: ");
+    for (int i = 0; i < properties.count(); i++) {
+        description.appendf("%s ", properties[i]);
+    }
+    description.appendf("MD5: %s", md5);
+
+    png_text text[2];
+    text[0].key  = (png_charp)"Author";
+    text[0].text = (png_charp)"DM unified Rec.2020";
+    text[0].compression = PNG_TEXT_COMPRESSION_NONE;
+    text[1].key  = (png_charp)"Description";
+    text[1].text = (png_charp)description.c_str();
+    text[1].compression = PNG_TEXT_COMPRESSION_NONE;
+    png_set_text(png, info, text, SK_ARRAY_COUNT(text));
+
+    png_init_io(png, f);
+    png_set_IHDR(png, info, (png_uint_32)fSize.width()
+                          , (png_uint_32)fSize.height()
+                          , 16/*bits per channel*/
+                          , PNG_COLOR_TYPE_RGB_ALPHA
+                          , PNG_INTERLACE_NONE
+                          , PNG_COMPRESSION_TYPE_DEFAULT
+                          , PNG_FILTER_TYPE_DEFAULT);
+
+    // Fastest encoding and decoding, at slight file size cost is no filtering, compression 1.
+    png_set_filter(png, PNG_FILTER_TYPE_BASE, PNG_FILTER_NONE);
+    // TODO(mtklein): set back to 1 after all the bots have cycled through new images / hashes?
+    png_set_compression_level(png, 9);
+
+    static const sk_sp<SkData> profile = SkWriteICCProfile(k2020_TF, SkNamedGamut::kRec2020);
+    png_set_iCCP(png, info,
+                 "Rec.2020",
+                 0/*compression type... no idea what options are available here*/,
+                 (png_const_bytep)profile->data(),
+                 (png_uint_32)    profile->size());
+
+    png_write_info(png, info);
+    for (int y = 0; y < fSize.height(); y++) {
+        png_write_row(png, (png_bytep)(fPixels.get() + y*fSize.width()));
+    }
+    png_write_end(png, info);
+
+    png_destroy_write_struct(&png, &info);
+    fclose(f);
+    return true;
+}
+