NOTE: I’m using this URL https://svgur.com/i/126b.svg for illustration purposes, the actual SVG is in my computer among my other files so CORS isn’t an issue.
OBJECTIVE
To use this SVG as a mask with the black parts being made transparent. This mask should be applied on the before pseudo-element and should cover the very bottommost part.
Below is my code and, underneath it, an image illustrating what I need. I’m using red to illustrate the area that should be revealed after applying the mask.
body {
margin: 0;
background: red;
}
#bg {
background: black;
width: 100vw;
height: 100vh;
}
#bg::before {
background-color: ;
background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='100%25' height='100%25' viewBox='0 0 1600 800'%3E%3Cg %3E%3Cpath fill='%23191a37' d='M486 705.8c-109.3-21.8-223.4-32.2-335.3-19.4C99.5 692.1 49 703 0 719.8V800h843.8c-115.9-33.2-230.8-68.1-347.6-92.2C492.8 707.1 489.4 706.5 486 705.8z'/%3E%3Cpath fill='%231e2044' d='M1600 0H0v719.8c49-16.8 99.5-27.8 150.7-33.5c111.9-12.7 226-2.4 335.3 19.4c3.4 0.7 6.8 1.4 10.2 2c116.8 24 231.7 59 347.6 92.2H1600V0z'/%3E%3Cpath fill='%23242550' d='M478.4 581c3.2 0.8 6.4 1.7 9.5 2.5c196.2 52.5 388.7 133.5 593.5 176.6c174.2 36.6 349.5 29.2 518.6-10.2V0H0v574.9c52.3-17.6 106.5-27.7 161.1-30.9C268.4 537.4 375.7 554.2 478.4 581z'/%3E%3Cpath fill='%23292b5d' d='M0 0v429.4c55.6-18.4 113.5-27.3 171.4-27.7c102.8-0.8 203.2 22.7 299.3 54.5c3 1 5.9 2 8.9 3c183.6 62 365.7 146.1 562.4 192.1c186.7 43.7 376.3 34.4 557.9-12.6V0H0z'/%3E%3Cpath fill='%232F3169' d='M181.8 259.4c98.2 6 191.9 35.2 281.3 72.1c2.8 1.1 5.5 2.3 8.3 3.4c171 71.6 342.7 158.5 531.3 207.7c198.8 51.8 403.4 40.8 597.3-14.8V0H0v283.2C59 263.6 120.6 255.7 181.8 259.4z'/%3E%3Cpath fill='%23343775' d='M1600 0H0v136.3c62.3-20.9 127.7-27.5 192.2-19.2c93.6 12.1 180.5 47.7 263.3 89.6c2.6 1.3 5.1 2.6 7.7 3.9c158.4 81.1 319.7 170.9 500.3 223.2c210.5 61 430.8 49 636.6-16.6V0z'/%3E%3Cpath fill='%233a3c81' d='M454.9 86.3C600.7 177 751.6 269.3 924.1 325c208.6 67.4 431.3 60.8 637.9-5.3c12.8-4.1 25.4-8.4 38.1-12.9V0H288.1c56 21.3 108.7 50.6 159.7 82C450.2 83.4 452.5 84.9 454.9 86.3z'/%3E%3Cpath fill='%233f428c' d='M1600 0H498c118.1 85.8 243.5 164.5 386.8 216.2c191.8 69.2 400 74.7 595 21.1c40.8-11.2 81.1-25.2 120.3-41.7V0z'/%3E%3Cpath fill='%23454798' d='M1397.5 154.8c47.2-10.6 93.6-25.3 138.6-43.8c21.7-8.9 43-18.8 63.9-29.5V0H643.4c62.9 41.7 129.7 78.2 202.1 107.4C1020.4 178.1 1214.2 196.1 1397.5 154.8z'/%3E%3Cpath fill='%234A4DA4' d='M1315.3 72.4c75.3-12.6 148.9-37.1 216.8-72.4h-723C966.8 71 1144.7 101 1315.3 72.4z'/%3E%3C/g%3E%3C/svg%3E");
background-attachment: fixed;
background-size: cover;
content: '';
width: 100%;
height: 100%;
position: absolute;
opacity: 0.3;
filter: saturate(0.2) brightness(1.1) contrast(1.25);
/*mask-image: url('https://svgur.com/i/126b.svg');*/
/*-webkit-mask-image: url('https://svgur.com/i/126b.svg');*/
}<div id="bg">
</div>It should look like this.
WHAT I’VE TRIED
Adding:
mask-image: url('https://svgur.com/i/126b.svg');
-webkit-mask-image: url('https://svgur.com/i/126b.svg');
and a few other things. I also tried troubleshooting with ChatGPT, to no avail.
NOTE
I already achieved what I wanted using clip-path as shown below. However, I’d still love to know why the previous approach wasn’t working, if somebody knows!
clip-path: polygon(
0 0, /* top left corner of the rectangle */
100% 0, /* top right corner of the rectangle */
100% 100vh, /* bottom right corner of the rectangle */
50% calc(100vh + 280px), /* tip of the triangle */
0 100vh /* bottom left corner of the rectangle */
);
2
Answers
put yout SVG inside the element, set the
position: absoluteandleft: 0; bottom: 0;to align it on bottom.If you need your mask svg to fit the parent elements width and height you can’t use
vworvhunits.Instead you scale and "squeeze" the mask-image via
CSS-masksize:100% 100Frankly, in your case css polygon based clip-paths are certainly the better option as they permit relative units by default.