gecko-dev/gfx/thebes/gfxFontMissingGlyphs.cpp

289 lines
10 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "gfxFontMissingGlyphs.h"
#include "gfxUtils.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/Helpers.h"
#include "mozilla/gfx/PathHelpers.h"
#include "mozilla/RefPtr.h"
#include "nsDeviceContext.h"
#include "nsLayoutUtils.h"
using namespace mozilla;
using namespace mozilla::gfx;
#define CHAR_BITS(b00, b01, b02, b10, b11, b12, b20, b21, b22, b30, b31, b32, b40, b41, b42) \
((b00 << 0) | (b01 << 1) | (b02 << 2) | (b10 << 3) | (b11 << 4) | (b12 << 5) | \
(b20 << 6) | (b21 << 7) | (b22 << 8) | (b30 << 9) | (b31 << 10) | (b32 << 11) | \
(b40 << 12) | (b41 << 13) | (b42 << 14))
static const uint16_t glyphMicroFont[16] = {
CHAR_BITS(0, 1, 0,
1, 0, 1,
1, 0, 1,
1, 0, 1,
0, 1, 0),
CHAR_BITS(0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0,
0, 1, 0),
CHAR_BITS(1, 1, 1,
0, 0, 1,
1, 1, 1,
1, 0, 0,
1, 1, 1),
CHAR_BITS(1, 1, 1,
0, 0, 1,
1, 1, 1,
0, 0, 1,
1, 1, 1),
CHAR_BITS(1, 0, 1,
1, 0, 1,
1, 1, 1,
0, 0, 1,
0, 0, 1),
CHAR_BITS(1, 1, 1,
1, 0, 0,
1, 1, 1,
0, 0, 1,
1, 1, 1),
CHAR_BITS(1, 1, 1,
1, 0, 0,
1, 1, 1,
1, 0, 1,
1, 1, 1),
CHAR_BITS(1, 1, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1,
0, 0, 1),
CHAR_BITS(0, 1, 0,
1, 0, 1,
0, 1, 0,
1, 0, 1,
0, 1, 0),
CHAR_BITS(1, 1, 1,
1, 0, 1,
1, 1, 1,
0, 0, 1,
0, 0, 1),
CHAR_BITS(1, 1, 1,
1, 0, 1,
1, 1, 1,
1, 0, 1,
1, 0, 1),
CHAR_BITS(1, 1, 0,
1, 0, 1,
1, 1, 0,
1, 0, 1,
1, 1, 0),
CHAR_BITS(0, 1, 1,
1, 0, 0,
1, 0, 0,
1, 0, 0,
0, 1, 1),
CHAR_BITS(1, 1, 0,
1, 0, 1,
1, 0, 1,
1, 0, 1,
1, 1, 0),
CHAR_BITS(1, 1, 1,
1, 0, 0,
1, 1, 1,
1, 0, 0,
1, 1, 1),
CHAR_BITS(1, 1, 1,
1, 0, 0,
1, 1, 1,
1, 0, 0,
1, 0, 0)
};
/* Parameters that control the rendering of hexboxes. They look like this:
BMP codepoints non-BMP codepoints
(U+0000 - U+FFFF) (U+10000 - U+10FFFF)
+---------+ +-------------+
| | | |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| | | |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| HHH HHH | | HHH HHH HHH |
| | | |
+---------+ +-------------+
*/
/** Width of a minifont glyph (see above) */
static const int MINIFONT_WIDTH = 3;
/** Height of a minifont glyph (see above) */
static const int MINIFONT_HEIGHT = 5;
/**
* Gap between minifont glyphs (both horizontal and vertical) and also
* the minimum desired gap between the box border and the glyphs
*/
static const int HEX_CHAR_GAP = 1;
/**
* The amount of space between the vertical edge of the glyphbox and the
* box border. We make this nonzero so that when multiple missing glyphs
* occur consecutively there's a gap between their rendered boxes.
*/
static const int BOX_HORIZONTAL_INSET = 1;
/** The width of the border */
static const int BOX_BORDER_WIDTH = 1;
/**
* The scaling factor for the border opacity; this is multiplied by the current
* opacity being used to draw the text.
*/
static const Float BOX_BORDER_OPACITY = 0.5;
/**
* Draw a single hex character using the current color. A nice way to do this
* would be to fill in an A8 image surface and then use it as a mask
* to paint the current color. Tragically this doesn't currently work with the
* Quartz cairo backend which doesn't generally support masking with surfaces.
* So for now we just paint a bunch of rectangles...
*/
#ifndef MOZ_GFX_OPTIMIZE_MOBILE
static void
DrawHexChar(uint32_t aDigit, const Point& aPt, DrawTarget& aDrawTarget,
const Pattern &aPattern)
{
// To avoid the potential for seams showing between rects when we're under
// a transform we concat all the rects into a PathBuilder and fill the
// resulting Path (rather than using DrawTarget::FillRect).
RefPtr<PathBuilder> builder = aDrawTarget.CreatePathBuilder();
uint32_t glyphBits = glyphMicroFont[aDigit];
for (int y = 0; y < MINIFONT_HEIGHT; ++y) {
for (int x = 0; x < MINIFONT_WIDTH; ++x) {
if (glyphBits & 1) {
Rect r(aPt.x + x, aPt.y + y, 1, 1);
MaybeSnapToDevicePixels(r, aDrawTarget, true);
builder->MoveTo(r.TopLeft());
builder->LineTo(r.TopRight());
builder->LineTo(r.BottomRight());
builder->LineTo(r.BottomLeft());
builder->Close();
}
glyphBits >>= 1;
}
}
RefPtr<Path> path = builder->Finish();
aDrawTarget.Fill(path, aPattern);
}
#endif // MOZ_GFX_OPTIMIZE_MOBILE
void
gfxFontMissingGlyphs::DrawMissingGlyph(uint32_t aChar,
const Rect& aRect,
DrawTarget& aDrawTarget,
const Pattern& aPattern,
uint32_t aAppUnitsPerDevPixel)
{
// If we're currently drawing with some kind of pattern, we just draw the
// missing-glyph data in black.
ColorPattern color = aPattern.GetType() == PatternType::COLOR ?
static_cast<const ColorPattern&>(aPattern) :
ColorPattern(ToDeviceColor(Color(0.f, 0.f, 0.f, 1.f)));
// Stroke a rectangle so that the stroke's left edge is inset one pixel
// from the left edge of the glyph box and the stroke's right edge
// is inset one pixel from the right edge of the glyph box.
Float halfBorderWidth = BOX_BORDER_WIDTH / 2.0;
Float borderLeft = aRect.X() + BOX_HORIZONTAL_INSET + halfBorderWidth;
Float borderRight = aRect.XMost() - BOX_HORIZONTAL_INSET - halfBorderWidth;
Rect borderStrokeRect(borderLeft, aRect.Y() + halfBorderWidth,
borderRight - borderLeft,
aRect.Height() - 2.0 * halfBorderWidth);
if (!borderStrokeRect.IsEmpty()) {
ColorPattern adjustedColor = color;
color.mColor.a *= BOX_BORDER_OPACITY;
#ifdef MOZ_GFX_OPTIMIZE_MOBILE
aDrawTarget.FillRect(borderStrokeRect, adjustedColor);
#else
StrokeOptions strokeOptions(BOX_BORDER_WIDTH);
aDrawTarget.StrokeRect(borderStrokeRect, adjustedColor, strokeOptions);
#endif
}
#ifndef MOZ_GFX_OPTIMIZE_MOBILE
Point center = aRect.Center();
Float halfGap = HEX_CHAR_GAP / 2.f;
Float top = -(MINIFONT_HEIGHT + halfGap);
// We always want integer scaling, otherwise the "bitmap" glyphs will look
// even uglier than usual when zoomed
int32_t devPixelsPerCSSPx =
std::max<int32_t>(1, nsDeviceContext::AppUnitsPerCSSPixel() /
aAppUnitsPerDevPixel);
AutoRestoreTransform autoRestoreTransform(&aDrawTarget);
aDrawTarget.SetTransform(
aDrawTarget.GetTransform().PreTranslate(center).
PreScale(devPixelsPerCSSPx,
devPixelsPerCSSPx));
if (aChar < 0x10000) {
if (aRect.Width() >= 2 * (MINIFONT_WIDTH + HEX_CHAR_GAP) &&
aRect.Height() >= 2 * MINIFONT_HEIGHT + HEX_CHAR_GAP) {
// Draw 4 digits for BMP
Float left = -(MINIFONT_WIDTH + halfGap);
DrawHexChar((aChar >> 12) & 0xF,
Point(left, top), aDrawTarget, color);
DrawHexChar((aChar >> 8) & 0xF,
Point(halfGap, top), aDrawTarget, color);
DrawHexChar((aChar >> 4) & 0xF,
Point(left, halfGap), aDrawTarget, color);
DrawHexChar(aChar & 0xF,
Point(halfGap, halfGap), aDrawTarget, color);
}
} else {
if (aRect.Width() >= 3 * (MINIFONT_WIDTH + HEX_CHAR_GAP) &&
aRect.Height() >= 2 * MINIFONT_HEIGHT + HEX_CHAR_GAP) {
// Draw 6 digits for non-BMP
Float first = -(MINIFONT_WIDTH * 1.5 + HEX_CHAR_GAP);
Float second = -(MINIFONT_WIDTH / 2.0);
Float third = (MINIFONT_WIDTH / 2.0 + HEX_CHAR_GAP);
DrawHexChar((aChar >> 20) & 0xF,
Point(first, top), aDrawTarget, color);
DrawHexChar((aChar >> 16) & 0xF,
Point(second, top), aDrawTarget, color);
DrawHexChar((aChar >> 12) & 0xF,
Point(third, top), aDrawTarget, color);
DrawHexChar((aChar >> 8) & 0xF,
Point(first, halfGap), aDrawTarget, color);
DrawHexChar((aChar >> 4) & 0xF,
Point(second, halfGap), aDrawTarget, color);
DrawHexChar(aChar & 0xF,
Point(third, halfGap), aDrawTarget, color);
}
}
#endif
}
Float
gfxFontMissingGlyphs::GetDesiredMinWidth(uint32_t aChar,
uint32_t aAppUnitsPerDevPixel)
{
/**
* The minimum desired width for a missing-glyph glyph box. I've laid it out
* like this so you can see what goes where.
*/
Float width = BOX_HORIZONTAL_INSET + BOX_BORDER_WIDTH + HEX_CHAR_GAP +
MINIFONT_WIDTH + HEX_CHAR_GAP + MINIFONT_WIDTH +
((aChar < 0x10000) ? 0 : HEX_CHAR_GAP + MINIFONT_WIDTH) +
HEX_CHAR_GAP + BOX_BORDER_WIDTH + BOX_HORIZONTAL_INSET;
// Note that this will give us floating-point division, so the width will
// -not- be snapped to integer multiples of its basic pixel value
width *= Float(nsDeviceContext::AppUnitsPerCSSPixel()) / aAppUnitsPerDevPixel;
return width;
}