body {
    font-family: 'Segoe UI', Arial, sans-serif;
}

.container {
    position: relative;
    width: 400px;
    height: 400px;
}

.canvas-overlay {
    position: absolute;
    top: 0;
    left: 0;
}

.controls {
    position: absolute;
    top: 0;
    left: 0;
    border: 1px dashed gray;
}

.control {
    position: absolute;
    width: 10px;
    height: 10px;
    background-color: gray;
    border: 1px solid #fff;
    box-sizing: border-box;
}

.control.tl {
    top: -5px;
    left: -5px;
}

.control.tr {
    top: -5px;
    right: -5px;
}

.control.bl {
    bottom: -5px;
    left: -5px;
}

.control.br {
    bottom: -5px;
    right: -5px;
}

.control.th {
    width: 11px;
    top: -5px;
    left: calc(50% - 5px);
}

.control.bh {
    bottom: -5px;
    left: calc(50% - 5px);
}

.control.lw {
    left: -5px;
    top: calc(50% - 5px);
}

.control.rw {
    right: -5px;
    top: calc(50% - 5px);
}

.control.rt {
    width: 11px;
    top: -50px;
    left: calc(50% - 5px);
    border-radius: 50%;
    border-color: #fff;
}

.control.rt::before {
    content: ' ';
    position: absolute;
    top: 9px;
    left: 4px;
    width: 1px;
    height: 35px;

    background-color: white;
}