nsresult
nsHTMLEditor::CheckPositionedElementBGandFG(nsIDOMElement * aElement,
nsAString & aReturn)
{
// we are going to outline the positioned element and bring it to the
// front to overlap any other element intersecting with it. But
// first, let's see what's the background and foreground colors of the
// positioned element.
// if background-image computed value is 'none,
// If the background color is 'auto' and R G B values of the foreground are
// each above #d0, use a black background
// If the background color is 'auto' and at least one of R G B values of
// the foreground is below #d0, use a white background
// Otherwise don't change background/foreground
nsCOMPtr<Element> element = do_QueryInterface(aElement);
NS_ENSURE_STATE(element || !aElement);
aReturn.Truncate();
nsAutoString bgImageStr;
nsresult res =
mHTMLCSSUtils->GetComputedProperty(*element, *nsGkAtoms::background_image,
bgImageStr);
NS_ENSURE_SUCCESS(res, res);
if (bgImageStr.EqualsLiteral("none")) {
nsAutoString bgColorStr;
res =
mHTMLCSSUtils->GetComputedProperty(*element, *nsGkAtoms::backgroundColor,
bgColorStr);
NS_ENSURE_SUCCESS(res, res);
if (bgColorStr.EqualsLiteral("transparent")) {
RefPtr<nsComputedDOMStyle> cssDecl =
mHTMLCSSUtils->GetComputedStyle(element);
NS_ENSURE_STATE(cssDecl);
// from these declarations, get the one we want and that one only
ErrorResult error;
RefPtr<dom::CSSValue> cssVal = cssDecl->GetPropertyCSSValue(NS_LITERAL_STRING("color"), error);
NS_ENSURE_TRUE(!error.Failed(), error.StealNSResult());
nsROCSSPrimitiveValue* val = cssVal->AsPrimitiveValue();
NS_ENSURE_TRUE(val, NS_ERROR_FAILURE);
if (nsIDOMCSSPrimitiveValue::CSS_RGBCOLOR == val->PrimitiveType()) {
nsDOMCSSRGBColor* rgbVal = val->GetRGBColorValue(error);
NS_ENSURE_TRUE(!error.Failed(), error.StealNSResult());
float r = rgbVal->Red()->
GetFloatValue(nsIDOMCSSPrimitiveValue::CSS_NUMBER, error);
NS_ENSURE_TRUE(!error.Failed(), error.StealNSResult());
float g = rgbVal->Green()->
GetFloatValue(nsIDOMCSSPrimitiveValue::CSS_NUMBER, error);
NS_ENSURE_TRUE(!error.Failed(), error.StealNSResult());
float b = rgbVal->Blue()->
GetFloatValue(nsIDOMCSSPrimitiveValue::CSS_NUMBER, error);
NS_ENSURE_TRUE(!error.Failed(), error.StealNSResult());
if (r >= BLACK_BG_RGB_TRIGGER &&
g >= BLACK_BG_RGB_TRIGGER &&
b >= BLACK_BG_RGB_TRIGGER)
aReturn.AssignLiteral("black");
else
aReturn.AssignLiteral("white");
return NS_OK;
}
}
}
return NS_OK;
}
