Re: [fxtf-drafts] Clarify the feTile area (#327)

Looks like it's really a *filter primitive region* issue. 

I've made 3 tests which in my opinion should all produce the exact results, but they are not:

```xml
<svg id="svg1" viewBox="0 0 200 200" xmlns="http://www.w3.org/2000/svg">
    <filter id="filter1">
        <feFlood flood-color="green" x="4" y="4" width="10" height="10"/>
        <feOffset dx="5" dy="5"/>
        <feTile x="50" y="50" width="100" height="100"/>
    </filter>
    <filter id="filter2">
        <feFlood flood-color="gray" x="4" y="4" width="10" height="10"/>
        <feOffset dx="5" dy="5"/>
        <feTile/>
    </filter>

    <rect id="rect2" x="20" y="20" width="160" height="160" filter="url(#filter2)"/>
    <rect id="rect1" x="20" y="20" width="160" height="160" filter="url(#filter1)"/>

    <rect id="rect3" x="50" y="50" width="100" height="100" fill="none" stroke="black"/>

    <rect id="frame" x="1" y="1" width="198" height="198" fill="none" stroke="black"/>
</svg>
```

![002](https://user-images.githubusercontent.com/725494/49342713-4d13ae80-f667-11e8-9a69-380a6c7d047e.png)

```xml
<svg id="svg1" viewBox="0 0 200 200" xmlns="http://www.w3.org/2000/svg">
    <filter id="filter1">
        <feFlood flood-color="green" x="20" y="20" width="10" height="10"/>
        <feOffset dx="5" dy="5"/>
        <feTile x="50" y="50" width="100" height="100"/>
    </filter>
    <filter id="filter2">
        <feFlood flood-color="gray" x="20" y="20" width="10" height="10"/>
        <feOffset dx="5" dy="5"/>
        <feTile/>
    </filter>

    <rect id="rect2" x="20" y="20" width="160" height="160" filter="url(#filter2)"/>
    <rect id="rect1" x="20" y="20" width="160" height="160" filter="url(#filter1)"/>

    <rect id="rect3" x="50" y="50" width="100" height="100" fill="none" stroke="black"/>

    <rect id="frame" x="1" y="1" width="198" height="198" fill="none" stroke="black"/>
</svg>
```

![005](https://user-images.githubusercontent.com/725494/49342709-3ff6bf80-f667-11e8-9fb0-c06f2890b958.png)

```xml
<svg id="svg1" viewBox="0 0 200 200" xmlns="http://www.w3.org/2000/svg">
    <filter id="filter1">
        <feFlood flood-color="green" x="2%" y="2%" width="10" height="10"/>
        <feOffset dx="5" dy="5"/>
        <feTile x="50" y="50" width="100" height="100"/>
    </filter>
    <filter id="filter2">
        <feFlood flood-color="gray" x="4" y="4" width="10" height="10"/>
        <feOffset dx="5" dy="5"/>
        <feTile/>
    </filter>

    <rect id="rect2" x="20" y="20" width="160" height="160" filter="url(#filter2)"/>
    <rect id="rect1" x="20" y="20" width="160" height="160" filter="url(#filter1)"/>

    <rect id="rect3" x="50" y="50" width="100" height="100" fill="none" stroke="black"/>

    <rect id="frame" x="1" y="1" width="198" height="198" fill="none" stroke="black"/>
</svg>
```

![006](https://user-images.githubusercontent.com/725494/49342994-f90ac900-f66a-11e8-85fc-593d192f1844.png)

And in short:

```xml
<feFlood flood-color="green" x="4" y="4" width="10" height="10"/>

<!-- it shouldn't matter where I've started, as long as the feTile input is 10x10px -->
<feFlood flood-color="green" x="20" y="20" width="10" height="10"/>

<!-- 2% == 4px -->
<feFlood flood-color="green" x="2%" y="2%" width="10" height="10"/>
```

Should they all be equal?

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Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/327#issuecomment-443526475 using your GitHub account

Received on Sunday, 2 December 2018 17:51:09 UTC