CSS3 Floats


This page contains the issues that are not yet listed in the specification and the resolutions for issues that were in the spec. but got resolved.

There is a companion use cases page.

General Note

Floats have a number of aspects/characteristics:

  1. The content if removed from normal flow
  2. A BFC is set up and shrink-wrapped
  3. The BFC is positioned
    1. Relative to the marker left behind when the content is removed
    2. Floats do not overlap one another and are stacked or cleared
    3. Positioning is limited to the “containing block”
  4. The BFC is an exclusion using it Border box as the wrap-shape

For exclusions,

  1. Positioning removes the content from normal flow (or the content is left in normal flow)
  2. Positioning also sets up a BFC and shrink-wraps it; wrap-shape may be default or explicit
  3. Positioning positions the exclusion,
    1. The marker is used to resolve “auto” values in absolute positioning
    2. The Exclusions proposal has groups and order to control exclusion interaction
    3. Interaction is not limited per b.
  4. The wrap-shape (or pair of shapes) is the exclusion.

We noted that “float” should have been better tied to “position” because it currently turns of the “position” property and replaces it.

Action Items

  • Vincent: add 'inherit' to all property values.
  • ACTION 356 Vincent: Make the default value for wrap-mode be auto
  • Vincent: Create a stub specification for CSS Floats.
  • Rossen. Write up the processing model for exclusions.
  • Editor. Note that the wrapping side (left, right, both) is always 'auto' for floats.
  • Editor. single trigger and wrap-shape propertyl. With wrap-shape: outside([shape [auto|both|left|right])|auto) inside(shape)
  • Editor. wrapping options are auto, left, right, both and none. Note that top and bottom is assumed for all values.
  • Editor. Add that we may consider having multiple shapes to define the inside and ouside shapes separately.
  • Editor. Add that we should have a 'wrap-shape-outline' or a 'stroke' property to let the user draw the outline of a wrap-shape
  • Editor. Clarify what happens when there are separate sub-shapes in an exclusion.


Issue 1: Processing model

Do one pass to position the exclusions. Then, do another pass with the exclusions present.

Issue 2: Exclusion trigger (what makes an element become an exclusion?)

Triggered with a single property that can specify that an inside or inside wrap-shape exists (or both), and how the content flows around the shape (for outside wrapping). Something like:

wrap-mode: default|none|inside|[outside-[left|right|both]|[all-[left+right+both] initial: default

Need to define default wrap-mode to be compatible with current float behavior. For example, a 'float: left' should have its default computed wrap-mode be 'outside-right', a 'float: right' would be 'outside-left'.

Issue 3: Containment model

Use the containing block model of CSS.

Issue 4: Enabling or disabling exclusions

Rename flow-wrap to something different like 'external exclusions allowed'.

Issue 5: Ordering of exclusions

Same as z-index. Should we have a separate property or not?

Proposal: use the same z-index property because having both z-index and an additional property may create issues and create surprising results.

Issue 6: Positioning of exclusions

As defined in CSS2.

Issue 7: Shrink wrap of container with floats having wrap-shapes (inside)

The shrink wrap is done with the float's box.

Issue 8: should we use something else than 'wrap'?

The use of 'wrap' in properties such as 'wrap-type' or 'wrap-mode' may be confusing because of a different meaning for wrap in the FlexBox specification ('flex-wrap' property) see Flex Box issues.

Issue 9: painting order and interactivity with exclusions

when an element has a wrap shape (inside our outside), what happens with events that happen within the element's box but outside the outside wrap-shape?
events are clipped to the 'outside' wrap-shape.

Issue 10: painting order and interactivity with exclusions

should the inside wrap shape be constrained to the outside wrap shape?
yes, the inside wrap shape should be clipped to the outside wrap shape.


Kyoto F2F June 2011, Friday

Make css3-floats module to bring together proposals for floats and exclusions

ideas/css3-floats.txt · Last modified: 2014/12/09 15:48 by
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