How does one scale a material to fit the entire space ?

[Z.]

Hey,
I need your help guys, i can't figure out how to re-size properly my HtmlMaterial so it fits the entire textured rect... I really don't understand how should I do, my code is only working fine with 1920 * 1080...
Here is the draw method :
function ENT:Draw()

  if self.Panel && self.Panel:GetHTMLMaterial() then

    local htmlMat = self.Panel:GetHTMLMaterial()

    local scaleX, scaleY = ScrW()/htmlMat:Width(),ScrH()/htmlMat:Height()

    local matData = {
      ["$basetexture"] = htmlMat:GetName(),
      ["$basetexturetransform"] = "center 0 0 scale " .. scaleX .. " " .. scaleY .. " rotate 0 translate 0 0",
      ["$model"] = 1
    }

    local uid = string.Replace(htmlMat:GetName(), "__vgui_texture_", "")

    self.Mat = CreateMaterial("WebMaterial_" .. uid, "UnlitGeneric", matData)

  end

  self:DrawModel()

  local DrawPos = self:LocalToWorld(Vector(1, -111, 58))

  local DrawAngles = self:GetAngles()
  DrawAngles:RotateAroundAxis(self:GetAngles():Forward(), 90)
  DrawAngles:RotateAroundAxis(self:GetAngles():Up(), 90)

  if self.Mat then

    cam.Start3D2D(DrawPos, DrawAngles, 0.4)

        surface.SetDrawColor(255,255,255, 255)
        surface.SetMaterial(self.Mat)
        surface.DrawTexturedRect(0, 0, 554, 290)

    cam.End3D2D()

  else

    cam.Start3D2D(DrawPos, DrawAngles, 0.4)

        surface.SetDrawColor(0, 0, 0, 255)
        surface.DrawRect(0, 0, 554, 290)

    cam.End3D2D()

  end

end
I don't understand at all how am i supposed to re-size it properly, i tough drawTexturedRect would make my material fill the whole rect but i was wrong... Can someone give me some tips ?
Merry xmas...