C++ RenderStyle::fontMetrics方法代码示例

GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const InlineTextBox* inlineTextBox)
{
    ASSERT(!inlineTextBox || inlineTextBox->lineStyle() == lineStyle);
    
    TextDecoration decoration = lineStyle.textDecorationsInEffect();
    if (decoration == TextDecorationNone)
        return GlyphOverflow();
    
    float strokeThickness = textDecorationStrokeThickness(lineStyle.fontSize());
    float controlPointDistance;
    float step;
    float wavyOffset;
        
    TextDecorationStyle decorationStyle = lineStyle.textDecorationStyle();
    float height = lineStyle.fontCascade().fontMetrics().floatHeight();
    GlyphOverflow overflowResult;
    
    if (decorationStyle == TextDecorationStyleWavy) {
        getWavyStrokeParameters(strokeThickness, controlPointDistance, step);
        wavyOffset = wavyOffsetFromDecoration();
        overflowResult.left = strokeThickness;
        overflowResult.right = strokeThickness;
    }

    // These metrics must match where underlines get drawn.
    if (decoration & TextDecorationUnderline) {
        // Compensate for the integral ceiling in GraphicsContext::computeLineBoundsAndAntialiasingModeForText()
        int underlineOffset = 1;
        underlineOffset += computeUnderlineOffset(lineStyle.textUnderlinePosition(), lineStyle.fontMetrics(), inlineTextBox, strokeThickness);
        if (decorationStyle == TextDecorationStyleWavy) {
            extendIntToFloat(overflowResult.bottom, underlineOffset + wavyOffset + controlPointDistance + strokeThickness - height);
            extendIntToFloat(overflowResult.top, -(underlineOffset + wavyOffset - controlPointDistance - strokeThickness));
        } else {
            extendIntToFloat(overflowResult.bottom, underlineOffset + strokeThickness - height);
            extendIntToFloat(overflowResult.top, -underlineOffset);
        }
    }
    if (decoration & TextDecorationOverline) {
        if (decorationStyle == TextDecorationStyleWavy) {
            extendIntToFloat(overflowResult.bottom, -wavyOffset + controlPointDistance + strokeThickness - height);
            extendIntToFloat(overflowResult.top, wavyOffset + controlPointDistance + strokeThickness);
        } else {
            extendIntToFloat(overflowResult.bottom, strokeThickness - height);
            // top is untouched
        }
    }
    if (decoration & TextDecorationLineThrough) {
        float baseline = lineStyle.fontMetrics().floatAscent();
        if (decorationStyle == TextDecorationStyleWavy) {
            extendIntToFloat(overflowResult.bottom, 2 * baseline / 3 + controlPointDistance + strokeThickness - height);
            extendIntToFloat(overflowResult.top, -(2 * baseline / 3 - controlPointDistance - strokeThickness));
        } else {
            extendIntToFloat(overflowResult.bottom, 2 * baseline / 3 + strokeThickness - height);
            extendIntToFloat(overflowResult.top, -(2 * baseline / 3));
        }
    }
    return overflowResult;
}

bool EllipsisBox::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, LayoutUnit lineTop, LayoutUnit lineBottom)
{
    LayoutPoint adjustedLocation = accumulatedOffset + roundedLayoutPoint(topLeft());

    // Hit test the markup box.
    if (InlineBox* markupBox = this->markupBox()) {
        RenderStyle* style = renderer().style(isFirstLineStyle());
        LayoutUnit mtx = adjustedLocation.x() + m_logicalWidth - markupBox->x();
        LayoutUnit mty = adjustedLocation.y() + style->fontMetrics().ascent() - (markupBox->y() + markupBox->renderer().style(isFirstLineStyle())->fontMetrics().ascent());
        if (markupBox->nodeAtPoint(request, result, locationInContainer, LayoutPoint(mtx, mty), lineTop, lineBottom)) {
            renderer().updateHitTestResult(result, locationInContainer.point() - LayoutSize(mtx, mty));
            return true;
        }
    }

    FloatPoint boxOrigin = locationIncludingFlipping();
    boxOrigin.moveBy(accumulatedOffset);
    FloatRect boundsRect(boxOrigin, size());
    if (visibleToHitTestRequest(request) && boundsRect.intersects(HitTestLocation::rectForPoint(locationInContainer.point(), 0, 0, 0, 0))) {
        renderer().updateHitTestResult(result, locationInContainer.point() - toLayoutSize(adjustedLocation));
        if (!result.addNodeToRectBasedTestResult(renderer().node(), request, locationInContainer, boundsRect))
            return true;
    }

    return false;
}

void EllipsisBox::paintMarkupBox(PaintInfo& paintInfo, const LayoutPoint& paintOffset, LayoutUnit lineTop, LayoutUnit lineBottom, const RenderStyle& style)
{
    InlineBox* markupBox = this->markupBox();
    if (!markupBox)
        return;

    LayoutPoint adjustedPaintOffset = paintOffset;
    adjustedPaintOffset.move(x() + m_logicalWidth - markupBox->x(),
        y() + style.fontMetrics().ascent() - (markupBox->y() + markupBox->lineStyle().fontMetrics().ascent()));
    markupBox->paint(paintInfo, adjustedPaintOffset, lineTop, lineBottom);
}

float SVGLengthContext::convertValueFromEXSToUserUnits(float value, ExceptionState& es) const
{
    RenderStyle* style = renderStyleForLengthResolving(m_context);
    if (!style) {
        es.throwDOMException(NotSupportedError);
        return 0;
    }

    // Use of ceil allows a pixel match to the W3Cs expected output of coords-units-03-b.svg
    // if this causes problems in real world cases maybe it would be best to remove this
    return value * ceilf(style->fontMetrics().xHeight());
}

float SVGLength::convertValueFromEXSToUserUnits(float value, const SVGElement* context, ExceptionCode& ec) const
{
    if (!context || !context->renderer() || !context->renderer()->style()) {
        ec = NOT_SUPPORTED_ERR;
        return 0;
    }

    RenderStyle* style = context->renderer()->style();
    // Use of ceil allows a pixel match to the W3Cs expected output of coords-units-03-b.svg
    // if this causes problems in real world cases maybe it would be best to remove this
    return value * ceilf(style->fontMetrics().xHeight());
}

LayoutUnit RenderMathMLFraction::baselinePosition(FontBaseline, bool firstLine, LineDirectionMode lineDirection, LinePositionMode linePositionMode) const
{
    if (firstChild() && firstChild()->isRenderMathMLBlock()) {
        RenderMathMLBlock* numerator = toRenderMathMLBlock(firstChild());
        RenderStyle* refStyle = style();
        if (previousSibling())
            refStyle = previousSibling()->style();
        else if (nextSibling())
            refStyle = nextSibling()->style();
        int shift = int(ceil((refStyle->fontMetrics().xHeight() + 1) / 2));
        return numerator->offsetHeight() + shift;
    }
    return RenderBlock::baselinePosition(AlphabeticBaseline, firstLine, lineDirection, linePositionMode);
}

float SVGLengthContext::convertValueFromUserUnitsToEXS(float value, ExceptionState& exceptionState) const
{
    RenderStyle* style = renderStyleForLengthResolving(m_context);
    if (!style) {
        exceptionState.throwDOMException(NotSupportedError, "No context could be found.");
        return 0;
    }

    // Use of ceil allows a pixel match to the W3Cs expected output of coords-units-03-b.svg
    // if this causes problems in real world cases maybe it would be best to remove this
    float xHeight = ceilf(style->fontMetrics().xHeight());
    if (!xHeight) {
        exceptionState.throwDOMException(NotSupportedError, "No x-height could be determined.");
        return 0;
    }

    return value / xHeight;
}

short RenderFlow::lineHeight(bool firstLine, bool isRootLineBox) const
{
    if (firstLine) {
        RenderStyle* s = style(firstLine);
        Length lh = s->lineHeight();
        if (lh.value < 0) {
            if (s == style()) {
                if (m_lineHeight == -1)
                    m_lineHeight = RenderObject::lineHeight(false);
                return m_lineHeight;
            }
            return s->fontMetrics().lineSpacing();
	}
        if (lh.isPercent())
            return lh.minWidth(s->font().pixelSize());
        return lh.value;
    }

    if (m_lineHeight == -1)
        m_lineHeight = RenderObject::lineHeight(false);
    return m_lineHeight;
}