blob: d9ca6d6bce841b8774049246f8e478673776eda0 [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/child/browser_font_resource_trusted.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "content/public/common/web_preferences.h"
#include "ppapi/c/dev/ppb_font_dev.h"
#include "ppapi/proxy/connection.h"
#include "ppapi/shared_impl/ppapi_preferences.h"
#include "ppapi/shared_impl/var.h"
#include "ppapi/thunk/enter.h"
#include "ppapi/thunk/ppb_image_data_api.h"
#include "ppapi/thunk/thunk.h"
#include "skia/ext/platform_canvas.h"
#include "third_party/WebKit/public/platform/WebCanvas.h"
#include "third_party/WebKit/public/platform/WebFloatPoint.h"
#include "third_party/WebKit/public/platform/WebFloatRect.h"
#include "third_party/WebKit/public/platform/WebRect.h"
#include "third_party/WebKit/public/web/WebFont.h"
#include "third_party/WebKit/public/web/WebFontDescription.h"
#include "third_party/WebKit/public/web/WebTextRun.h"
#include "third_party/icu/source/common/unicode/ubidi.h"
#include "third_party/skia/include/core/SkRect.h"
using ppapi::StringVar;
using ppapi::thunk::EnterResourceNoLock;
using ppapi::thunk::PPB_ImageData_API;
using blink::WebFloatPoint;
using blink::WebFloatRect;
using blink::WebFont;
using blink::WebFontDescription;
using blink::WebRect;
using blink::WebTextRun;
using blink::WebCanvas;
namespace content {
namespace {
// Same as WebPreferences::kCommonScript. I'd use that directly here, but get an
// undefined reference linker error.
const char kCommonScript[] = "Zyyy";
base::string16 GetFontFromMap(const ScriptFontFamilyMap& map,
const std::string& script) {
ScriptFontFamilyMap::const_iterator it = map.find(script);
if (it != map.end())
return it->second;
return base::string16();
// Splits a PP_BrowserFont_Trusted_TextRun into a sequence or LTR and RTL
// WebTextRuns that can be used for WebKit. Normally WebKit does this for us,
// but the font drawing and measurement routines we call happen after this
// step. So for correct rendering of RTL content, we need to do it ourselves.
class TextRunCollection {
explicit TextRunCollection(const PP_BrowserFont_Trusted_TextRun& run)
: bidi_(NULL),
num_runs_(0) {
StringVar* text_string = StringVar::FromPPVar(run.text);
if (!text_string)
return; // Leave num_runs_ = 0 so we'll do nothing.
text_ = base::UTF8ToUTF16(text_string->value());
if (run.override_direction) {
// Skip autodetection.
num_runs_ = 1;
override_run_ = WebTextRun(text_, PP_ToBool(run.rtl), true);
} else {
bidi_ = ubidi_open();
UErrorCode uerror = U_ZERO_ERROR;
ubidi_setPara(bidi_,, text_.size(), run.rtl, NULL, &uerror);
if (U_SUCCESS(uerror))
num_runs_ = ubidi_countRuns(bidi_, &uerror);
~TextRunCollection() {
if (bidi_)
const base::string16& text() const { return text_; }
int num_runs() const { return num_runs_; }
// Returns a WebTextRun with the info for the run at the given index.
// The range covered by the run is in the two output params.
WebTextRun GetRunAt(int index, int32_t* run_start, int32_t* run_len) const {
DCHECK(index < num_runs_);
if (bidi_) {
bool run_rtl = !!ubidi_getVisualRun(bidi_, index, run_start, run_len);
return WebTextRun(base::string16(&text_[*run_start], *run_len),
run_rtl, true);
// Override run, return the single one.
DCHECK(index == 0);
*run_start = 0;
*run_len = static_cast<int32_t>(text_.size());
return override_run_;
// Will be null if we skipped autodetection.
UBiDi* bidi_;
// Text of all the runs.
base::string16 text_;
int num_runs_;
// When the content specifies override_direction (bidi_ is null) then this
// will contain the single text run for WebKit.
WebTextRun override_run_;
bool PPTextRunToWebTextRun(const PP_BrowserFont_Trusted_TextRun& text,
WebTextRun* run) {
StringVar* text_string = StringVar::FromPPVar(text.text);
if (!text_string)
return false;
*run = WebTextRun(base::UTF8ToUTF16(text_string->value()),
return true;
// The PP_* version lacks "None", so is just one value shifted from the
// WebFontDescription version. These values are checked in
// PPFontDescToWebFontDesc to make sure the conversion is correct. This is a
// macro so it can also be used in the static_asserts.
static_cast<WebFontDescription::GenericFamily>(f + 1)
// Assumes the given PP_FontDescription has been validated.
WebFontDescription PPFontDescToWebFontDesc(
const PP_BrowserFont_Trusted_Description& font,
const ppapi::Preferences& prefs) {
// Verify that the enums match so we can just static cast.
static_assert(static_cast<int>(WebFontDescription::Weight100) ==
"font Weight100");
static_assert(static_cast<int>(WebFontDescription::Weight900) ==
"font Weight900");
static_assert(WebFontDescription::GenericFamilyStandard ==
static_assert(WebFontDescription::GenericFamilySerif ==
static_assert(WebFontDescription::GenericFamilySansSerif ==
static_assert(WebFontDescription::GenericFamilyMonospace ==
StringVar* face_name = StringVar::FromPPVar(font.face); // Possibly null.
WebFontDescription result;
base::string16 resolved_family;
if (!face_name || face_name->value().empty()) {
// Resolve the generic family.
switch ( {
resolved_family = GetFontFromMap(prefs.serif_font_family_map,
resolved_family = GetFontFromMap(prefs.sans_serif_font_family_map,
resolved_family = GetFontFromMap(prefs.fixed_font_family_map,
resolved_family = GetFontFromMap(prefs.standard_font_family_map,
} else {
// Use the exact font.
resolved_family = base::UTF8ToUTF16(face_name->value());
} = resolved_family;
result.genericFamily = PP_FAMILY_TO_WEB_FAMILY(;
if (font.size == 0) {
// Resolve the default font size, using the resolved family to see if
// we should use the fixed or regular font size. It's difficult at this
// level to detect if the requested font is fixed width, so we only apply
// the alternate font size to the default fixed font family.
if (base::ToLowerASCII(resolved_family) ==
result.size = static_cast<float>(prefs.default_fixed_font_size);
result.size = static_cast<float>(prefs.default_font_size);
} else {
// Use the exact size.
result.size = static_cast<float>(font.size);
result.italic = font.italic != PP_FALSE;
result.smallCaps = font.small_caps != PP_FALSE;
result.weight = static_cast<WebFontDescription::Weight>(font.weight);
result.letterSpacing = static_cast<short>(font.letter_spacing);
result.wordSpacing = static_cast<short>(font.word_spacing);
return result;
} // namespace
// static
bool BrowserFontResource_Trusted::IsPPFontDescriptionValid(
const PP_BrowserFont_Trusted_Description& desc) {
// Check validity of string. We can't check the actual text since we could
// be on the wrong thread and don't know if we're in the plugin or the host.
if (desc.face.type != PP_VARTYPE_STRING &&
desc.face.type != PP_VARTYPE_UNDEFINED)
return false;
// Check enum ranges.
return false;
if (static_cast<int>(desc.weight) < PP_BROWSERFONT_TRUSTED_WEIGHT_100 ||
static_cast<int>(desc.weight) > PP_BROWSERFONT_TRUSTED_WEIGHT_900)
return false;
// Check for excessive sizes which may cause layout to get confused.
if (desc.size > 200)
return false;
return true;
ppapi::proxy::Connection connection,
PP_Instance instance,
const PP_BrowserFont_Trusted_Description& desc,
const ppapi::Preferences& prefs)
: PluginResource(connection, instance),
font_(WebFont::create(PPFontDescToWebFontDesc(desc, prefs))) {
BrowserFontResource_Trusted::~BrowserFontResource_Trusted() {
BrowserFontResource_Trusted::AsPPB_BrowserFont_Trusted_API() {
return this;
PP_Bool BrowserFontResource_Trusted::Describe(
PP_BrowserFont_Trusted_Description* description,
PP_BrowserFont_Trusted_Metrics* metrics) {
if (description->face.type != PP_VARTYPE_UNDEFINED)
return PP_FALSE;
// While converting the other way in PPFontDescToWebFontDesc we validated
// that the enums can be casted.
WebFontDescription web_desc = font_->fontDescription();
description->face = StringVar::StringToPPVar(base::UTF16ToUTF8(
description->family =
description->size = static_cast<uint32_t>(web_desc.size);
description->weight = static_cast<PP_BrowserFont_Trusted_Weight>(
description->italic = web_desc.italic ? PP_TRUE : PP_FALSE;
description->small_caps = web_desc.smallCaps ? PP_TRUE : PP_FALSE;
description->letter_spacing = static_cast<int32_t>(web_desc.letterSpacing);
description->word_spacing = static_cast<int32_t>(web_desc.wordSpacing);
metrics->height = font_->height();
metrics->ascent = font_->ascent();
metrics->descent = font_->descent();
metrics->line_spacing = font_->lineSpacing();
metrics->x_height = static_cast<int32_t>(font_->xHeight());
// Convert the string.
return PP_TRUE;
PP_Bool BrowserFontResource_Trusted::DrawTextAt(
PP_Resource image_data,
const PP_BrowserFont_Trusted_TextRun* text,
const PP_Point* position,
uint32_t color,
const PP_Rect* clip,
PP_Bool image_data_is_opaque) {
PP_Bool result = PP_FALSE;
// Get and map the image data we're painting to.
EnterResourceNoLock<PPB_ImageData_API> enter(image_data, true);
if (enter.failed())
return result;
PPB_ImageData_API* image = static_cast<PPB_ImageData_API*>(
SkCanvas* canvas = image->GetPlatformCanvas();
bool needs_unmapping = false;
if (!canvas) {
needs_unmapping = true;
canvas = image->GetPlatformCanvas();
if (!canvas)
return result; // Failure mapping.
if (!PP_ToBool(image_data_is_opaque)) {
// Ideally, LCD text should be configured at canvas creation time using
// SkSurfaceProps. But because the API exposes image_data_is_opaque per
// draw text call (allowing clients to essentially change their mind),
// we have to handle it here.
SkImageInfo info;
size_t row_bytes;
void* pixels = canvas->accessTopLayerPixels(&info, &row_bytes);
if (!pixels)
return result;
SkBitmap bm;
if (!bm.installPixels(info, pixels, row_bytes))
return result;
SkSurfaceProps props(0, kUnknown_SkPixelGeometry);
SkCanvas temp_canvas(bm, props);
DrawTextToCanvas(&temp_canvas, *text, position, color, clip);
} else {
DrawTextToCanvas(canvas, *text, position, color, clip);
if (needs_unmapping)
return PP_TRUE;
int32_t BrowserFontResource_Trusted::MeasureText(
const PP_BrowserFont_Trusted_TextRun* text) {
WebTextRun run;
if (!PPTextRunToWebTextRun(*text, &run))
return -1;
return font_->calculateWidth(run);
uint32_t BrowserFontResource_Trusted::CharacterOffsetForPixel(
const PP_BrowserFont_Trusted_TextRun* text,
int32_t pixel_position) {
TextRunCollection runs(*text);
int32_t cur_pixel_offset = 0;
for (int i = 0; i < runs.num_runs(); i++) {
int32_t run_begin = 0;
int32_t run_len = 0;
WebTextRun run = runs.GetRunAt(i, &run_begin, &run_len);
int run_width = font_->calculateWidth(run);
if (pixel_position < cur_pixel_offset + run_width) {
// Offset is in this run.
return static_cast<uint32_t>(font_->offsetForPosition(
run, static_cast<float>(pixel_position - cur_pixel_offset))) +
cur_pixel_offset += run_width;
return runs.text().size();
int32_t BrowserFontResource_Trusted::PixelOffsetForCharacter(
const PP_BrowserFont_Trusted_TextRun* text,
uint32_t char_offset) {
TextRunCollection runs(*text);
int32_t cur_pixel_offset = 0;
for (int i = 0; i < runs.num_runs(); i++) {
int32_t run_begin = 0;
int32_t run_len = 0;
WebTextRun run = runs.GetRunAt(i, &run_begin, &run_len);
if (char_offset >= static_cast<uint32_t>(run_begin) &&
char_offset < static_cast<uint32_t>(run_begin + run_len)) {
// Character we're looking for is in this run.
// Here we ask WebKit to give us the rectangle around the character in
// question, and then return the left edge. If we asked for a range of
// 0 characters starting at the character in question, it would give us
// a 0-width rect around the insertion point. But that will be on the
// right side of the character for an RTL run, which would be wrong.
WebFloatRect rect = font_->selectionRectForText(
run, WebFloatPoint(0.0f, 0.0f), font_->height(),
char_offset - run_begin, char_offset - run_begin + 1);
return cur_pixel_offset + static_cast<int>(rect.x);
} else {
// Character is past this run, account for the pixels and continue
// looking.
cur_pixel_offset += font_->calculateWidth(run);
return -1; // Requested a char beyond the end.
void BrowserFontResource_Trusted::DrawTextToCanvas(
SkCanvas* destination,
const PP_BrowserFont_Trusted_TextRun& text,
const PP_Point* position,
uint32_t color,
const PP_Rect* clip) {
// Convert position and clip.
WebFloatPoint web_position(static_cast<float>(position->x),
WebRect web_clip;
if (!clip) {
// Use entire canvas. SkCanvas doesn't have a size on it, so we just use
// the current clip bounds.
SkRect skclip;
web_clip = WebRect(skclip.fLeft, skclip.fTop, skclip.fRight - skclip.fLeft,
skclip.fBottom - skclip.fTop);
} else {
web_clip = WebRect(clip->point.x, clip->point.y,
clip->size.width, clip->size.height);
TextRunCollection runs(text);
for (int i = 0; i < runs.num_runs(); i++) {
int32_t run_begin = 0;
int32_t run_len = 0;
WebTextRun run = runs.GetRunAt(i, &run_begin, &run_len);
font_->drawText(destination, run, web_position, color, web_clip);
// Advance to the next run. Note that we avoid doing this for the last run
// since it's unnecessary, measuring text is slow, and most of the time
// there will be only one run anyway.
if (i != runs.num_runs() - 1)
web_position.x += font_->calculateWidth(run);
} // namespace content