added the readme

shaders/ImageBox.frag

@@ -0,0 +1,37 @@
+#version 330 core
+out vec4 FragColor;
+  
+in vec2 TexCoords;
+
+uniform float rounding = 0.0f;
+
+uniform vec2 screenSize;
+uniform vec2 normalizedCenterPos;
+uniform vec2 normalizedCenterScale;
+uniform vec2 pixelScale;
+uniform vec2 pixelPos;
+
+uniform vec4 Color = {0.0f,0.0f,0.0f,1.0f};
+uniform vec4 BackgroundColor = {0.0f,0.0f,0.0f,1.0f};
+
+uniform sampler2D tex;
+
+void main()
+{ 
+    FragColor = Color * texture(tex,TexCoords);
+    
+
+    float rounding = clamp(rounding,0.0f,1.0f);
+    if (rounding != 0.0f) {
+        float roundingfactor = min(pixelScale.x,pixelScale.y)/2 * rounding;
+        vec2 r1 = pixelScale/2 - vec2(roundingfactor);
+        vec2 absrelcoord = abs(gl_FragCoord.xy - pixelScale/2 -  pixelPos);
+    
+        if (!(absrelcoord.x < r1.x || absrelcoord.y < r1.y)) {
+            if (pow(absrelcoord.y-r1.y,2) > pow(roundingfactor,2) - pow((absrelcoord.x-r1.x),2)) {
+                discard;
+        }
+    }
+    }
+    
+}