294 lines
8.0 KiB
C++
294 lines
8.0 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "mozilla/ArrayUtils.h" // for ArrayLength
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#include "mozilla/mozalloc.h" // for operator delete, etc
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#include "nsColor.h"
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#include <sys/types.h> // for int32_t
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#include "nsColorNames.h" // for nsColorNames
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#include "nsDebug.h" // for NS_ASSERTION, etc
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#include "nsStaticNameTable.h"
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#include "nsString.h" // for nsAutoCString, nsString, etc
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#include "nscore.h" // for nsAString, etc
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using namespace mozilla;
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// define an array of all color names
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#define GFX_COLOR(_name, _value) #_name,
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static const char* const kColorNames[] = {
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#include "nsColorNameList.h"
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};
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#undef GFX_COLOR
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// define an array of all color name values
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#define GFX_COLOR(_name, _value) _value,
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static const nscolor kColors[] = {
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#include "nsColorNameList.h"
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};
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#undef GFX_COLOR
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#define eColorName_COUNT (ArrayLength(kColorNames))
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#define eColorName_UNKNOWN (-1)
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static nsStaticCaseInsensitiveNameTable* gColorTable = nullptr;
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void nsColorNames::AddRefTable(void)
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{
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NS_ASSERTION(!gColorTable, "pre existing array!");
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if (!gColorTable) {
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gColorTable =
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new nsStaticCaseInsensitiveNameTable(kColorNames, eColorName_COUNT);
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}
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}
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void nsColorNames::ReleaseTable(void)
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{
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if (gColorTable) {
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delete gColorTable;
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gColorTable = nullptr;
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}
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}
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static int ComponentValue(const char16_t* aColorSpec, int aLen, int color, int dpc)
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{
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int component = 0;
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int index = (color * dpc);
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if (2 < dpc) {
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dpc = 2;
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}
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while (--dpc >= 0) {
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char16_t ch = ((index < aLen) ? aColorSpec[index++] : '0');
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if (('0' <= ch) && (ch <= '9')) {
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component = (component * 16) + (ch - '0');
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} else if ((('a' <= ch) && (ch <= 'f')) ||
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(('A' <= ch) && (ch <= 'F'))) {
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// "ch&7" handles lower and uppercase hex alphabetics
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component = (component * 16) + (ch & 7) + 9;
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}
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else { // not a hex digit, treat it like 0
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component = (component * 16);
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}
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}
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return component;
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}
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bool NS_HexToRGB(const nsAString& aColorSpec, nscolor* aResult)
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{
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const char16_t* buffer = aColorSpec.BeginReading();
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int nameLen = aColorSpec.Length();
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if ((nameLen == 3) || (nameLen == 6)) {
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// Make sure the digits are legal
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for (int i = 0; i < nameLen; i++) {
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char16_t ch = buffer[i];
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if (((ch >= '0') && (ch <= '9')) ||
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((ch >= 'a') && (ch <= 'f')) ||
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((ch >= 'A') && (ch <= 'F'))) {
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// Legal character
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continue;
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}
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// Whoops. Illegal character.
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return false;
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}
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// Convert the ascii to binary
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int dpc = ((3 == nameLen) ? 1 : 2);
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// Translate components from hex to binary
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int r = ComponentValue(buffer, nameLen, 0, dpc);
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int g = ComponentValue(buffer, nameLen, 1, dpc);
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int b = ComponentValue(buffer, nameLen, 2, dpc);
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if (dpc == 1) {
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// Scale single digit component to an 8 bit value. Replicate the
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// single digit to compute the new value.
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r = (r << 4) | r;
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g = (g << 4) | g;
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b = (b << 4) | b;
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}
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NS_ASSERTION((r >= 0) && (r <= 255), "bad r");
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NS_ASSERTION((g >= 0) && (g <= 255), "bad g");
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NS_ASSERTION((b >= 0) && (b <= 255), "bad b");
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*aResult = NS_RGB(r, g, b);
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return true;
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}
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// Improperly formatted color value
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return false;
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}
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// This implements part of the algorithm for legacy behavior described in
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// http://www.whatwg.org/specs/web-apps/current-work/complete/common-microsyntaxes.html#rules-for-parsing-a-legacy-color-value
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bool NS_LooseHexToRGB(const nsString& aColorSpec, nscolor* aResult)
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{
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if (aColorSpec.EqualsLiteral("transparent")) {
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return false;
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}
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int nameLen = aColorSpec.Length();
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const char16_t* colorSpec = aColorSpec.get();
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if (nameLen > 128) {
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nameLen = 128;
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}
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if ('#' == colorSpec[0]) {
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++colorSpec;
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--nameLen;
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}
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// digits per component
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int dpc = (nameLen + 2) / 3;
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int newdpc = dpc;
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// Use only the rightmost 8 characters of each component.
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if (newdpc > 8) {
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nameLen -= newdpc - 8;
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colorSpec += newdpc - 8;
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newdpc = 8;
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}
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// And then keep trimming characters at the left until we'd trim one
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// that would leave a nonzero value, but not past 2 characters per
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// component.
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while (newdpc > 2) {
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bool haveNonzero = false;
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for (int c = 0; c < 3; ++c) {
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MOZ_ASSERT(c * dpc < nameLen,
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"should not pass end of string while newdpc > 2");
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char16_t ch = colorSpec[c * dpc];
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if (('1' <= ch && ch <= '9') ||
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('A' <= ch && ch <= 'F') ||
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('a' <= ch && ch <= 'f')) {
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haveNonzero = true;
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break;
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}
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}
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if (haveNonzero) {
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break;
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}
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--newdpc;
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--nameLen;
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++colorSpec;
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}
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// Translate components from hex to binary
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int r = ComponentValue(colorSpec, nameLen, 0, dpc);
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int g = ComponentValue(colorSpec, nameLen, 1, dpc);
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int b = ComponentValue(colorSpec, nameLen, 2, dpc);
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NS_ASSERTION((r >= 0) && (r <= 255), "bad r");
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NS_ASSERTION((g >= 0) && (g <= 255), "bad g");
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NS_ASSERTION((b >= 0) && (b <= 255), "bad b");
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*aResult = NS_RGB(r, g, b);
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return true;
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}
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bool NS_ColorNameToRGB(const nsAString& aColorName, nscolor* aResult)
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{
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if (!gColorTable) return false;
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int32_t id = gColorTable->Lookup(aColorName);
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if (eColorName_UNKNOWN < id) {
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NS_ASSERTION(uint32_t(id) < eColorName_COUNT,
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"gColorTable->Lookup messed up");
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if (aResult) {
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*aResult = kColors[id];
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}
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return true;
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}
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return false;
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}
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// Returns kColorNames, an array of all possible color names, and sets
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// *aSizeArray to the size of that array. Do NOT call free() on this array.
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const char * const * NS_AllColorNames(size_t *aSizeArray)
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{
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*aSizeArray = ArrayLength(kColorNames);
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return kColorNames;
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}
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// Macro to blend two colors
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//
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// equivalent to target = (bg*(255-fgalpha) + fg*fgalpha)/255
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#define MOZ_BLEND(target, bg, fg, fgalpha) \
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FAST_DIVIDE_BY_255(target, (bg)*(255-fgalpha) + (fg)*(fgalpha))
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nscolor
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NS_ComposeColors(nscolor aBG, nscolor aFG)
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{
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// This function uses colors that are non premultiplied alpha.
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int r, g, b, a;
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int bgAlpha = NS_GET_A(aBG);
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int fgAlpha = NS_GET_A(aFG);
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// Compute the final alpha of the blended color
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// a = fgAlpha + bgAlpha*(255 - fgAlpha)/255;
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FAST_DIVIDE_BY_255(a, bgAlpha*(255-fgAlpha));
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a = fgAlpha + a;
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int blendAlpha;
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if (a == 0) {
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// In this case the blended color is totally trasparent,
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// we preserve the color information of the foreground color.
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blendAlpha = 255;
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} else {
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blendAlpha = (fgAlpha*255)/a;
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}
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MOZ_BLEND(r, NS_GET_R(aBG), NS_GET_R(aFG), blendAlpha);
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MOZ_BLEND(g, NS_GET_G(aBG), NS_GET_G(aFG), blendAlpha);
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MOZ_BLEND(b, NS_GET_B(aBG), NS_GET_B(aFG), blendAlpha);
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return NS_RGBA(r, g, b, a);
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}
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// Functions to convert from HSL color space to RGB color space.
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// This is the algorithm described in the CSS3 specification
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// helper
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static float
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HSL_HueToRGB(float m1, float m2, float h)
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{
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if (h < 0.0f)
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h += 1.0f;
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if (h > 1.0f)
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h -= 1.0f;
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if (h < (float)(1.0/6.0))
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return m1 + (m2 - m1)*h*6.0f;
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if (h < (float)(1.0/2.0))
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return m2;
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if (h < (float)(2.0/3.0))
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return m1 + (m2 - m1)*((float)(2.0/3.0) - h)*6.0f;
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return m1;
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}
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// The float parameters are all expected to be in the range 0-1
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nscolor
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NS_HSL2RGB(float h, float s, float l)
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{
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uint8_t r, g, b;
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float m1, m2;
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if (l <= 0.5f) {
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m2 = l*(s+1);
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} else {
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m2 = l + s - l*s;
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}
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m1 = l*2 - m2;
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r = uint8_t(255 * HSL_HueToRGB(m1, m2, h + 1.0f/3.0f));
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g = uint8_t(255 * HSL_HueToRGB(m1, m2, h));
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b = uint8_t(255 * HSL_HueToRGB(m1, m2, h - 1.0f/3.0f));
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return NS_RGB(r, g, b);
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}
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const char*
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NS_RGBToColorName(nscolor aColor)
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{
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for (size_t idx = 0; idx < ArrayLength(kColors); ++idx) {
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if (kColors[idx] == aColor) {
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return kColorNames[idx];
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}
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}
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return nullptr;
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}
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