From b08de46480420c891207abddabe599ba4c978773 Mon Sep 17 00:00:00 2001 From: Andreas Kling Date: Mon, 18 Nov 2019 12:21:37 +0100 Subject: [PATCH] LibHTML: Implement basic 'max-width' and 'min-width' support These CSS properties constrain the computed width of a block-level box to a maximum, followed by a minimum value. This makes the "better mother fricken website" look more like it's intended to (which helps makes the author's point, I suppose.) --- Libraries/LibHTML/Layout/LayoutBlock.cpp | 131 ++++++++++++++--------- 1 file changed, 82 insertions(+), 49 deletions(-) diff --git a/Libraries/LibHTML/Layout/LayoutBlock.cpp b/Libraries/LibHTML/Layout/LayoutBlock.cpp index f5cb6f3935..15705d82c8 100644 --- a/Libraries/LibHTML/Layout/LayoutBlock.cpp +++ b/Libraries/LibHTML/Layout/LayoutBlock.cpp @@ -157,66 +157,99 @@ void LayoutBlock::compute_width() auto auto_value = Length(); auto zero_value = Length(0, Length::Type::Absolute); - auto width = style.length_or_fallback(CSS::PropertyID::Width, auto_value); - auto margin_left = style.length_or_fallback(CSS::PropertyID::MarginLeft, zero_value); - auto margin_right = style.length_or_fallback(CSS::PropertyID::MarginRight, zero_value); - auto border_left = style.length_or_fallback(CSS::PropertyID::BorderLeftWidth, zero_value); - auto border_right = style.length_or_fallback(CSS::PropertyID::BorderRightWidth, zero_value); - auto padding_left = style.length_or_fallback(CSS::PropertyID::PaddingLeft, zero_value); - auto padding_right = style.length_or_fallback(CSS::PropertyID::PaddingRight, zero_value); + + Length margin_left; + Length margin_right; + Length border_left; + Length border_right; + Length padding_left; + Length padding_right; + + auto try_compute_width = [&](const auto& a_width) { + Length width = a_width; +#ifdef HTML_DEBUG + dbg() << " Left: " << margin_left << "+" << border_left << "+" << padding_left; + dbg() << "Right: " << margin_right << "+" << border_right << "+" << padding_right; +#endif + margin_left = style.length_or_fallback(CSS::PropertyID::MarginLeft, zero_value); + margin_right = style.length_or_fallback(CSS::PropertyID::MarginRight, zero_value); + border_left = style.length_or_fallback(CSS::PropertyID::BorderLeftWidth, zero_value); + border_right = style.length_or_fallback(CSS::PropertyID::BorderRightWidth, zero_value); + padding_left = style.length_or_fallback(CSS::PropertyID::PaddingLeft, zero_value); + padding_right = style.length_or_fallback(CSS::PropertyID::PaddingRight, zero_value); + + int total_px = 0; + for (auto& value : { margin_left, border_left, padding_left, width, padding_right, border_right, margin_right }) { + total_px += value.to_px(); + } #ifdef HTML_DEBUG - dbg() << " Left: " << margin_left << "+" << border_left << "+" << padding_left; - dbg() << "Right: " << margin_right << "+" << border_right << "+" << padding_right; + dbg() << "Total: " << total_px; #endif - int total_px = 0; - for (auto& value : { margin_left, border_left, padding_left, width, padding_right, border_right, margin_right }) { - total_px += value.to_px(); - } + // 10.3.3 Block-level, non-replaced elements in normal flow + // If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' (plus any of 'margin-left' or 'margin-right' that are not 'auto') is larger than the width of the containing block, then any 'auto' values for 'margin-left' or 'margin-right' are, for the following rules, treated as zero. + if (width.is_auto() && total_px > containing_block()->width()) { + if (margin_left.is_auto()) + margin_left = zero_value; + if (margin_right.is_auto()) + margin_right = zero_value; + } -#ifdef HTML_DEBUG - dbg() << "Total: " << total_px; -#endif + // 10.3.3 cont'd. + auto underflow_px = containing_block()->width() - total_px; - // 10.3.3 Block-level, non-replaced elements in normal flow - // If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' (plus any of 'margin-left' or 'margin-right' that are not 'auto') is larger than the width of the containing block, then any 'auto' values for 'margin-left' or 'margin-right' are, for the following rules, treated as zero. - if (width.is_auto() && total_px > containing_block()->width()) { - if (margin_left.is_auto()) - margin_left = zero_value; - if (margin_right.is_auto()) - margin_right = zero_value; - } - - // 10.3.3 cont'd. - auto underflow_px = containing_block()->width() - total_px; - - if (width.is_auto()) { - if (margin_left.is_auto()) - margin_left = zero_value; - if (margin_right.is_auto()) - margin_right = zero_value; - if (underflow_px >= 0) { - width = Length(underflow_px, Length::Type::Absolute); + if (width.is_auto()) { + if (margin_left.is_auto()) + margin_left = zero_value; + if (margin_right.is_auto()) + margin_right = zero_value; + if (underflow_px >= 0) { + width = Length(underflow_px, Length::Type::Absolute); + } else { + width = zero_value; + margin_right = Length(margin_right.to_px() + underflow_px, Length::Type::Absolute); + } } else { - width = zero_value; - margin_right = Length(margin_right.to_px() + underflow_px, Length::Type::Absolute); + if (!margin_left.is_auto() && !margin_right.is_auto()) { + margin_right = Length(margin_right.to_px() + underflow_px, Length::Type::Absolute); + } else if (!margin_left.is_auto() && margin_right.is_auto()) { + margin_right = Length(underflow_px, Length::Type::Absolute); + } else if (margin_left.is_auto() && !margin_right.is_auto()) { + margin_left = Length(underflow_px, Length::Type::Absolute); + } else { // margin_left.is_auto() && margin_right.is_auto() + auto half_of_the_underflow = Length(underflow_px / 2, Length::Type::Absolute); + margin_left = half_of_the_underflow; + margin_right = half_of_the_underflow; + } } - } else { - if (!margin_left.is_auto() && !margin_right.is_auto()) { - margin_right = Length(margin_right.to_px() + underflow_px, Length::Type::Absolute); - } else if (!margin_left.is_auto() && margin_right.is_auto()) { - margin_right = Length(underflow_px, Length::Type::Absolute); - } else if (margin_left.is_auto() && !margin_right.is_auto()) { - margin_left = Length(underflow_px, Length::Type::Absolute); - } else { // margin_left.is_auto() && margin_right.is_auto() - auto half_of_the_underflow = Length(underflow_px / 2, Length::Type::Absolute); - margin_left = half_of_the_underflow; - margin_right = half_of_the_underflow; + return width; + }; + + auto specified_width = style.length_or_fallback(CSS::PropertyID::Width, auto_value); + + // 1. The tentative used width is calculated (without 'min-width' and 'max-width') + auto used_width = try_compute_width(specified_width); + + // 2. The tentative used width is greater than 'max-width', the rules above are applied again, + // but this time using the computed value of 'max-width' as the computed value for 'width'. + auto specified_max_width = style.length_or_fallback(CSS::PropertyID::MaxWidth, auto_value); + if (!specified_max_width.is_auto()) { + if (used_width.to_px() > specified_max_width.to_px()) { + used_width = try_compute_width(specified_max_width); } } - rect().set_width(width.to_px()); + // 3. If the resulting width is smaller than 'min-width', the rules above are applied again, + // but this time using the value of 'min-width' as the computed value for 'width'. + auto specified_min_width = style.length_or_fallback(CSS::PropertyID::MinWidth, auto_value); + if (!specified_min_width.is_auto()) { + if (used_width.to_px() < specified_min_width.to_px()) { + used_width = try_compute_width(specified_min_width); + } + } + + rect().set_width(used_width.to_px()); box_model().margin().left = margin_left; box_model().margin().right = margin_right; box_model().border().left = border_left;