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// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/public/common/color_parser.h"
#include <stdint.h>
#include <algorithm>
#include <cmath>
#include "base/containers/contains.h"
#include "base/notimplemented.h"
#include "base/numerics/safe_conversions.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "third_party/re2/src/re2/re2.h"
#include "third_party/skia/include/utils/SkParse.h"
#include "ui/gfx/color_utils.h"
namespace content {
namespace {
bool ParseHslColorString(const std::string& color_string, SkColor* result) {
// http://www.w3.org/wiki/CSS/Properties/color/HSL#The_format_of_the_HSL_Value
// The CSS3 specification defines the format of a HSL color as
// hsl(<number>, <percent>, <percent>)
// and with alpha, the format is
// hsla(<number>, <percent>, <percent>, <number>)
// e.g.: hsl(120, 100%, 50%), hsla(120, 100%, 50%, 0.5);
double hue = 0.0;
double saturation = 0.0;
double lightness = 0.0;
// 'hsl()' has '1' alpha value implicitly.
double alpha = 1.0;
if (!re2::RE2::FullMatch(color_string,
"hsl\\((-?[\\d.]+),\\s*([\\d.]+)%,\\s*([\\d.]+)%\\)",
&hue, &saturation, &lightness) &&
!re2::RE2::FullMatch(
color_string,
"hsla\\((-?[\\d.]+),\\s*([\\d.]+)%,\\s*([\\d.]+)%,\\s*([\\d.]+)\\)",
&hue, &saturation, &lightness, &alpha)) {
return false;
}
color_utils::HSL hsl;
// Normalize the value between 0.0 and 1.0.
hsl.h = (((static_cast<int>(hue) % 360) + 360) % 360) / 360.0;
hsl.s = std::clamp(saturation, 0.0, 100.0) / 100.0;
hsl.l = std::clamp(lightness, 0.0, 100.0) / 100.0;
SkAlpha sk_alpha = std::clamp(alpha, 0.0, 1.0) * 255;
*result = color_utils::HSLToSkColor(hsl, sk_alpha);
return true;
}
} // anonymous namespace
bool ParseCssColorString(const std::string& color_string, SkColor* result) {
if (color_string.empty())
return false;
if (color_string[0] == '#')
return ParseHexColorString(color_string, result);
if (base::StartsWith(color_string, "hsl", base::CompareCase::SENSITIVE))
return ParseHslColorString(color_string, result);
if (base::StartsWith(color_string, "rgb", base::CompareCase::SENSITIVE)) {
return ParseRgbColorString(color_string, result);
}
if (SkParse::FindNamedColor(color_string.c_str(), color_string.size(),
result) != nullptr) {
return true;
}
return false;
}
bool ParseHexColorString(const std::string& color_string, SkColor* result) {
std::string formatted_color;
// Save a memory allocation -- we never need more than 8 chars.
formatted_color.reserve(8);
// Check the string for incorrect formatting.
if (color_string.empty() || color_string[0] != '#')
return false;
// Convert the string from #FFF format to #FFFFFF format.
if (color_string.length() == 4 || color_string.length() == 5) {
for (size_t i = 1; i < color_string.length(); ++i) {
formatted_color += color_string[i];
formatted_color += color_string[i];
}
} else if (color_string.length() == 7) {
formatted_color.assign(color_string, 1, 6);
} else if (color_string.length() == 9) {
formatted_color.assign(color_string, 1, 8);
} else {
return false;
}
// Add an alpha if one was not set.
if (formatted_color.length() == 6) {
formatted_color += "FF";
}
// Convert the hex string to an integer.
std::array<uint8_t, 4> color_bytes;
if (!base::HexStringToSpan(formatted_color, color_bytes))
return false;
*result = SkColorSetARGB(color_bytes[3], color_bytes[0], color_bytes[1],
color_bytes[2]);
return true;
}
bool ParseRgbColorString(const std::string& color_string, SkColor* result) {
// https://www.w3.org/wiki/CSS/Properties/color/RGB#The_format_of_the_RGB_Value
// The CSS3 specification defines the format of a RGB color as
// rgb(<number>, <number>, <number>) or
// rgb(<percent>, <percent>, <percent>) or
// and with alpha, the format is
// rgb(<number>, <number>, <number>, <alphavalue>) or
// rgba(<percent>, <percent>, <percent>, <alphavalue>)
// Whitespace is arbitrary.
// e.g.: rgb(120, 100, 50), rgba(120, 100, 50, 0.5);
int r = 0;
int g = 0;
int b = 0;
// 'rgb()' has '1' alpha value implicitly.
double alpha = 1.0;
// Percentage rgb values are not supported.
if (base::Contains(color_string, '%')) {
NOTIMPLEMENTED();
return false;
}
if (!re2::RE2::FullMatch(color_string,
"rgb\\(([\\d]+),\\s*([\\d]+),\\s*([\\d]+)\\)", &r,
&g, &b) &&
!re2::RE2::FullMatch(
color_string,
"rgba\\(([\\d]+),\\s*([\\d]+),\\s*([\\d]+),\\s*([\\d.]+)\\)", &r, &g,
&b, &alpha)) {
return false;
}
if (alpha < 0 || alpha > 1.0 || r < 0 || r > 255 || g < 0 || g > 255 ||
b < 0 || b > 255) {
return false;
}
SkAlpha sk_alpha = alpha * 255;
*result = SkColorSetARGB(sk_alpha, r, g, b);
return true;
}
} // namespace content
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