[css-tables] Defined grid, row, column, etc; fixes #603

Author: FremyCompany

css-tables-3/Overview.bs

@@ -114,7 +114,7 @@ spec:css22; type:property; text:display
 
 	To summarize, an instance of the table model consists of:
 	<ul class="compact">
-		<li>Its <a href="#table-root-element">table-root element</a> containing:
+		<li>Its <a href="#table-root-element">table-root</a> containing:
 		<ul>
 			<li>Zero, one or more <a href="#table-row">table rows</a>, optionally in <a href="#table-row-grouping-element">row groups</a>,
 				<ul><li>Each of them contaning one or more <a href="#table-cell">table cells</a></li></ul>
@@ -268,15 +268,35 @@ spec:css22; type:property; text:display
 				A sequence of sibling boxes is consecutive
 					if each box in the sequence is consecutive to the one before it in the sequence.
 
-			<dt><dfn id="table-slot">slot</dfn>
+			<dt><dfn id="table-grid">table grid</dfn>
 			<dd>
-				A <a>slot</a> is an available space created
-					by the intersection of a row and a column in the table grid.
+				A matrix 
+					containing as many <dfn id="row">rows</dfn> and <dfn id="column">columns</dfn>
+					as needed to describe the position of all the <a>table-rows</a> and <a>table-cells</a> of a <a>table-root</a>,
+					as determined by the <a href="#dimensioning-the-row-column-grid">grid-dimensioning algorithm</a>.
+				
+				Each row of the grid might correspond to a <a>table-row</a>, and each column to a <a>table-column</a>.
+
+			<dt><dfn id="slot">slot</dfn> of the table grid.
+			<dd>
+				A <a>slot</a> <code>(r,c)</code> is an available space created
+					by the intersection of a row <code>r</code> and a column <code>c</code> in the <a>table grid</a>.
+				
+				Each slot of the table grid is covered by at least one <a>table-cell</a> (<a href="#missing-cells-fixup">some of them anonymous</a>), and at most two.
+				Each table-cell of a table-root covers at least one slot. 
+				
+				Table-cells that cover more than one slot do so densely, 
+					meaning the set of slots it covers can always be described as a set of four strictly-positive integers <code>(rowMin, colMin, rowSpan, colSpan)</code>
+					such that a slot <code>(r,c)</code> is covered by the table-cell 
+						if and only if <code>r</code> lies in the interval between <code>rowMin</code> (included) and <code>rowMin+rowSpan</code> (not included), 
+						and <code>c</code> lies in the interval between <code>colMin</code> (included) and <code>colMin+colSpan</code> (not included);
+				
+				Such table-cell is said to <dfn>originate</dfn> from row <code>rowMin</code> and column <code>colMin</code> (and, by extension, the corresponding table-tracks).
+
+				Such table-cell is said to <dfn>span</dfn> all rows <code>r</code> and columns <code>c</code> matching the above condition (and, by extension, the corresponding table-tracks).
 
 		</dl>
 
-		ISSUE(603): Define the table grid
-
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@@ -295,10 +315,10 @@ spec:css22; type:property; text:display
 		Any descendant of a <a>table-root</a> that is not table-internal
 			must have a set of ancestors in the table consisting of
 			at least three nested objects corresponding to
-			a <a>table</a>/<a>inline-table</a> element,
-			a <a>table-row</a> element, and
-			a <a>table-cell</a> element.
-		Missing elements cause the generation of <a href="#fixup-boxes">anonymous boxes</a> according to the following rules:
+			a <a>table</a>/<a>inline-table</a>,
+			a <a>table-row</a>, and
+			a <a>table-cell</a>.
+		Missing boxes cause the generation of <a href="#fixup-boxes">anonymous boxes</a> according to the following rules:
 
 		<!--——————————————————————————————————————————————————————————————————————————-->
 		<h4 id="fixup-algorithm">Fixup Algorithm</h4>
@@ -581,12 +601,20 @@ spec:css22; type:property; text:display
 		Like mentioned in the <a href="#table-structure">Table structure</a> section,
 			how many rows and columns a table has
 			can be determined from the table structure.
-		Both dimensioning the row/column grid and assigning table-cells their <nobr>slot(s)</nobr> in that grid
+		Both dimensioning the row/column <a>grid<a> and assigning table-cells their <nobr><a>slot</a>(s)</nobr> in that grid
 			do require running the HTML Algorithms for tables.
 
+		<h4 id="dimensioning-the-row-column-grid--step1">HTML Algorithm</h4>
 		<p class="note">
 			CSS Boxes that do not originate from an HTML table element equivalent to their display type
-				need to be converted to their HTML equivalent before we can apply this algorithm.
+				need to be converted to their HTML equivalent before we can apply this algorithm, see below.
+			There is no way to specify the <a>span</a> of a cell in css only in this level of the spec,
+				the use of an HTML td element is required to do so.
+
+		Apply the <a href="https://www.w3.org/TR/html5/tabular-data.html#forming-a-table">HTML5 Table Formatting algorithm</a>,
+			where boxes act like <a href="#display-types">the HTML element equivalent to their display type</a>,
+			and use the attributes of their originating element if and only if it is an HTML element of the same type
+			(otherwise, they act like if they didnt't have any attribute).
 
 		<div class="example">
 			<xmp class="lang-markup">
@@ -661,11 +689,7 @@ spec:css22; type:property; text:display
 
 		</div>
 
-		Apply the <a href="https://www.w3.org/TR/html5/tabular-data.html#forming-a-table">HTML5 Table Formatting algorithm</a>,
-			where boxes act like <a href="#display-types">the HTML element equivalent to their display type</a>,
-			and use the attributes of their originating element only if it as an HTML element of the same type
-			(otherwise, they act like they didnt't have any attribute).
-
+		<h4 id="dimensioning-the-row-column-grid--step2">Track merging</h4>
 		<p class="note">
 			The HTML Table Formatting algorithm sometimes generates more tracks than necessary to layout the table properly.
 			Those tracks have historically been ignored by user agents,
@@ -686,7 +710,7 @@ spec:css22; type:property; text:display
 		For tables <a>in fixed mode</a>, only rows are eligible to be merged that way; which means that every column is preserved.
 
 		Finally, assign to the <a>table-root</a> element its correct number of rows and columns (from its mapped element),
-			and to each <a>table-cell</a> element its accurate table-row-start/table-column-start/table-row-span/table-column-span (from its mapped element).
+			and to each <a>table-cell</a> element its accurate <a href="#slot">rowMin/colMin/rowSpan/colSpan</a> (from its mapped element).
 
 	<!--——————————————————————————————————————————————————————————————————————————-->
 	<h3 id="missing-cells-fixup">Missing cells fixup</h3>