Use hypothetical main size for collecting lines and choosing factor

DRKV333 · DRKV333 · commit 792bfe351c80 · 2025-08-23T18:45:59.000Z
diff --git a/include/litehtml/flex_item.h b/include/litehtml/flex_item.h
@@ -15,10 +15,13 @@ namespace litehtml
 	{
 	public:
 		std::shared_ptr<render_item> el;
+
+		// All sizes should be interpreted as outer/margin-box sizes.
 		pixel_t base_size;
 		pixel_t min_size;
 		def_value<pixel_t> max_size;
-		pixel_t main_size;
+		pixel_t main_size; // Holds the outer hypothetical main size before distribute_free_space, and the used outer main size after.
+
 		int grow;
 		int shrink;
 		pixel_t scaled_flex_shrink_factor;
diff --git a/src/flex_item.cpp b/src/flex_item.cpp
@@ -28,7 +28,18 @@ void litehtml::flex_item::init(const litehtml::containing_block_context &self_si
 	{
 		align = el->css().get_flex_align_self();
 	}
-	main_size = base_size;
+
+	if (base_size < min_size)
+	{
+		main_size = min_size;
+	} else if (!max_size.is_default() && base_size > max_size)
+	{
+		main_size = max_size;
+	} else
+	{
+		main_size = base_size;
+	}
+
 	scaled_flex_shrink_factor = base_size * shrink;
 	frozen = false;
 }
diff --git a/src/flex_line.cpp b/src/flex_line.cpp
@@ -7,7 +7,7 @@ void litehtml::flex_line::distribute_free_space(pixel_t container_main_size)
 	// Determine the used flex factor. Sum the outer hypothetical main sizes of all items on the line.
 	// If the sum is less than the flex container’s inner main size, use the flex grow factor for the
 	// rest of this algorithm; otherwise, use the flex shrink factor.
-	pixel_t initial_free_space = container_main_size - base_size;
+	pixel_t initial_free_space = container_main_size - main_size;
 	bool grow;
 	int total_flex_factor;
 	if(initial_free_space < 0)
@@ -21,7 +21,7 @@ void litehtml::flex_line::distribute_free_space(pixel_t container_main_size)
 		{
 			for(auto &item : items)
 			{
-				item->main_size += initial_free_space * item->shrink / 1000;
+				item->main_size = item->base_size + initial_free_space * item->shrink / 1000;
 			}
 			return;
 		}
@@ -36,7 +36,7 @@ void litehtml::flex_line::distribute_free_space(pixel_t container_main_size)
 		{
 			for(auto &item : items)
 			{
-				item->main_size += initial_free_space * item->grow / 1000;
+				item->main_size = item->base_size + initial_free_space * item->grow / 1000;
 			}
 			return;
 		}
@@ -195,16 +195,16 @@ void litehtml::flex_line::init(pixel_t container_main_size, bool fit_container,
 							   const litehtml::containing_block_context &self_size,
 							   litehtml::formatting_context *fmt_ctx)
 {
-	cross_size = 0;
-	main_size = 0;
-	first_baseline.set(0, baseline::baseline_type_none);
-	last_baseline.set(0, baseline::baseline_type_none);
-
 	if(!fit_container)
 	{
 		distribute_free_space(container_main_size);
 	}
 
+	cross_size = 0;
+	main_size = 0;
+	first_baseline.set(0, baseline::baseline_type_none);
+	last_baseline.set(0, baseline::baseline_type_none);
+	
 	if(is_row_direction)
 	{
 		def_value<pixel_t> first_baseline_top = 0;
diff --git a/src/render_flex.cpp b/src/render_flex.cpp
@@ -301,12 +301,13 @@ std::list<litehtml::flex_line> litehtml::render_item_flex::get_lines(const liteh
 	// Add flex items to lines
 	for(auto& item : items)
 	{
-		if(!line.items.empty() && !single_line && line.base_size + item->base_size > container_main_size)
+		if(!line.items.empty() && !single_line && line.main_size + item->main_size > container_main_size)
 		{
 			lines.emplace_back(line);
 			line = flex_line(reverse_main, reverse_cross);
 		}
 		line.base_size += item->base_size;
+		line.main_size += item->main_size;
 		line.total_grow += item->grow;
 		line.total_shrink += item->shrink;
 		if(!item->auto_margin_main_start.is_default()) line.num_auto_margin_main_start++;

Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@ void litehtml::flex_line::distribute_free_space(pixel_t container_main_size)`
`7`	`7`	`// Determine the used flex factor. Sum the outer hypothetical main sizes of all items on the line.`
`8`	`8`	`// If the sum is less than the flex container’s inner main size, use the flex grow factor for the`
`9`	`9`	`// rest of this algorithm; otherwise, use the flex shrink factor.`
`10`		`- pixel_t initial_free_space = container_main_size - base_size;`
	`10`	`+ pixel_t initial_free_space = container_main_size - main_size;`
`11`	`11`	`bool grow;`
`12`	`12`	`int total_flex_factor;`
`13`	`13`	`if(initial_free_space < 0)`
`@@ -21,7 +21,7 @@ void litehtml::flex_line::distribute_free_space(pixel_t container_main_size)`
`21`	`21`	`{`
`22`	`22`	`for(auto &item : items)`
`23`	`23`	`{`
`24`		`- item->main_size += initial_free_space * item->shrink / 1000;`
	`24`	`+ item->main_size = item->base_size + initial_free_space * item->shrink / 1000;`
`25`	`25`	`}`
`26`	`26`	`return;`
`27`	`27`	`}`
`@@ -36,7 +36,7 @@ void litehtml::flex_line::distribute_free_space(pixel_t container_main_size)`
`36`	`36`	`{`
`37`	`37`	`for(auto &item : items)`
`38`	`38`	`{`
`39`		`- item->main_size += initial_free_space * item->grow / 1000;`
	`39`	`+ item->main_size = item->base_size + initial_free_space * item->grow / 1000;`
`40`	`40`	`}`
`41`	`41`	`return;`
`42`	`42`	`}`
`@@ -195,16 +195,16 @@ void litehtml::flex_line::init(pixel_t container_main_size, bool fit_container,`
`195`	`195`	`const litehtml::containing_block_context &self_size,`
`196`	`196`	`litehtml::formatting_context *fmt_ctx)`
`197`	`197`	`{`
`198`		`- cross_size = 0;`
`199`		`- main_size = 0;`
`200`		`- first_baseline.set(0, baseline::baseline_type_none);`
`201`		`- last_baseline.set(0, baseline::baseline_type_none);`
`202`		`-`
`203`	`198`	`if(!fit_container)`
`204`	`199`	`{`
`205`	`200`	`distribute_free_space(container_main_size);`
`206`	`201`	`}`
`207`	`202`
	`203`	`+ cross_size = 0;`
	`204`	`+ main_size = 0;`
	`205`	`+ first_baseline.set(0, baseline::baseline_type_none);`
	`206`	`+ last_baseline.set(0, baseline::baseline_type_none);`
	`207`	`+`
`208`	`208`	`if(is_row_direction)`
`209`	`209`	`{`
`210`	`210`	`def_value<pixel_t> first_baseline_top = 0;`
Original file line number	Diff line number	Diff line change
`@@ -301,12 +301,13 @@ std::list<litehtml::flex_line> litehtml::render_item_flex::get_lines(const liteh`
`301`	`301`	`// Add flex items to lines`
`302`	`302`	`for(auto& item : items)`
`303`	`303`	`{`
`304`		`- if(!line.items.empty() && !single_line && line.base_size + item->base_size > container_main_size)`
	`304`	`+ if(!line.items.empty() && !single_line && line.main_size + item->main_size > container_main_size)`
`305`	`305`	`{`
`306`	`306`	`lines.emplace_back(line);`
`307`	`307`	`line = flex_line(reverse_main, reverse_cross);`
`308`	`308`	`}`
`309`	`309`	`line.base_size += item->base_size;`
	`310`	`+ line.main_size += item->main_size;`
`310`	`311`	`line.total_grow += item->grow;`
`311`	`312`	`line.total_shrink += item->shrink;`
`312`	`313`	`if(!item->auto_margin_main_start.is_default()) line.num_auto_margin_main_start++;`