Maybe you want to use CSS "clip-path" (Works with transparency and background)
"clip-path" reference: https://developer.mozilla.org/en-US/docs/Web/CSS/clip-path
Generator: http://bennettfeely.com/clippy/
Example:
/* With percent */_x000D_
.element-percent {_x000D_
background: red;_x000D_
width: 150px;_x000D_
height: 48px;_x000D_
display: inline-block;_x000D_
_x000D_
clip-path: polygon(0 0, 100% 0%, 75% 100%, 0% 100%);_x000D_
}_x000D_
_x000D_
/* With pixel */_x000D_
.element-pixel {_x000D_
background: blue;_x000D_
width: 150px;_x000D_
height: 48px;_x000D_
display: inline-block;_x000D_
_x000D_
clip-path: polygon(0 0, 100% 0%, calc(100% - 32px) 100%, 0% 100%);_x000D_
}_x000D_
_x000D_
/* With background */_x000D_
.element-background {_x000D_
background: url(https://images.pexels.com/photos/170811/pexels-photo-170811.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=750&w=1260) no-repeat center/cover;_x000D_
width: 150px;_x000D_
height: 48px;_x000D_
display: inline-block;_x000D_
_x000D_
clip-path: polygon(0 0, 100% 0%, calc(100% - 32px) 100%, 0% 100%);_x000D_
}
_x000D_
<div class="element-percent"></div>_x000D_
_x000D_
<br />_x000D_
_x000D_
<div class="element-pixel"></div>_x000D_
_x000D_
<br />_x000D_
_x000D_
<div class="element-background"></div>
_x000D_