catgl_ui_slider.h

void caDrawSlider(NVGcontext* vg, float pos, float x, float y, float w, float h)
{
	NVGpaint bg, knob;
	float cy = y+(int)(h*0.5f);
	float kr = (int)(h*0.25f);

	nvgSave(vg);
//	nvgClearState(vg);

	// Slot
	bg = nvgBoxGradient(vg, x,cy-2+1, w,4, 2,2, nvgRGBA(0,0,0,32), nvgRGBA(0,0,0,128));
	nvgBeginPath(vg);
	nvgRoundedRect(vg, x,cy-2, w,4, 2);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	// Knob Shadow
	bg = nvgRadialGradient(vg, x+(int)(pos*w),cy+1, kr-3,kr+3, nvgRGBA(0,0,0,64), nvgRGBA(0,0,0,0));
	nvgBeginPath(vg);
	nvgRect(vg, x+(int)(pos*w)-kr-5,cy-kr-5,kr*2+5+5,kr*2+5+5+3);
	nvgCircle(vg, x+(int)(pos*w),cy, kr);
	nvgPathWinding(vg, NVG_HOLE);
	nvgFillPaint(vg, bg);
	nvgFill(vg);

	// Knob
	knob = nvgLinearGradient(vg, x,cy-kr,x,cy+kr, nvgRGBA(255,255,255,16), nvgRGBA(0,0,0,16));
	nvgBeginPath(vg);
	nvgCircle(vg, x+(int)(pos*w),cy, kr-1);
	nvgFillColor(vg, nvgRGBA(40,43,48,255));
	nvgFill(vg);
	nvgFillPaint(vg, knob);
	nvgFill(vg);

	nvgBeginPath(vg);
	nvgCircle(vg, x+(int)(pos*w),cy, kr-0.5f);
	nvgStrokeColor(vg, nvgRGBA(0,0,0,92));
	nvgStroke(vg);

	nvgRestore(vg);
}