/*  text on ....
   This is a rework of version 3 of write.scad to use the new OpenSCAD internal text() primitive.
   All credit to Harlan Martin (harlan@sutlog.com) for his great effort on the original.
   Great thanks to t-paul (and the OpenSCAD dev team) on adding the new text() primitive.
*/


/*
The arguments to be provided for each function are explictly in the modules.

All modules take close to all the arguments to text() [Not all features are supported in all text_on_object() modules though -- try them out warnings will be given if it is not supported]

text() params:
t
size
spacing
font
direction -- ltr, ttb, btt or rtl
language
script
halign -- left, right or center
valign -- baseline, bottom, top or center

All modules also take the additional arguments:
extrusion_height = depth of the letter, i.e. how far it sits proud
rotate
center //center the text at the location it is being written (NOT that the object is centered)

ALL faux-objects that the text is applied to have center=true
TODO: object_center=true/false (already done for cylinder)

The above arguemnts can be seen in text_extrude() as all modules call that module evetually (often multiple times).

locn_vector -- Where the faux-object has been translated to. TODO: Rename object to translate_vector?

Additional arguments for text_on_cube():

Additional arguments for text_on_cylinder():

Additional arguments for text_on_circle():

Additional arguments for text_on_sphere():


*/

// These control the default values for text_extrude(), text_on_sphere(), text_on_cube(), text_on_cylinder(), text_on_circle()
// if the arguments are not included in the call to the module.

// Defaults
// Defaults for all modules
default_t="text_on";
default_size = 4; //TODO - Can we make this 10?? To match internal size? There is an underlying value in text() -- This masks that.
default_font = "Liberation Mono";
default_spacing = 1; //Spacing between characters. There is an underlying value in text() -- This masks that. We try and match it here.
default_rotate  = 0; // text rotation (clockwise)
default_center  = true; //Text-centering
default_scale = [1,1,1];
default_extrusion_height = 2; //mm letter extrusion height

//Defaults for Cube
default_cube_face        = "front";	 // default face (top,bottom,left,right,back,front)
default_sphere_rounded   = false;	 //default for rounded letters on text_on_sphere
default_cube_updown = 0; //mm up (-down) from center on face of cube
default_cube_rightleft = 0;		 //mm right(-left) from center on face of cube

//Defaults for Sphere
default_sphere_northsouth= 0;
default_sphere_eastwest  = 0;
default_sphere_spin      = 0; //TODO:Different to rotate? or up/down. Better name?

//Defaults for Cylinder (including circle as it is on top/bottom)
default_circle_middle    = 0;      //(mm toward middle of circle)
default_circle_ccw       = false;  //write on top or bottom in a ccw direction
default_circle_eastwest  = 0;
default_cylinder_face    = "side";
default_cylinder_updown  = 0;

//Internal values - don't play with these :)
//This is much more accurate than the PI constant internal to Openscad.
internal_pi=3.1415926535897932384626433832795028841971693993751058209;
internal_pi2=internal_pi*2;

//Internal values - You might want to play with these if you are using a proportional font
internal_space_fudge = 0.80; //Fudge for working out lengths (widths) of strings

debug = true;

//---- Helper Functions ----
//String width (length from left to right or RTL) in OpenSCAD units
//NOTE: These are innacurate because we don't know the real spacing of the chars and so have to approximate
//They work for monospaced (fixed-width) fonts well
function width_of_text_char( size, spacing ) = (size * internal_space_fudge * spacing);
function width_of_text_string_num_length(length, size, spacing) = ( width_of_text_char( size, spacing ) * (length));
function width_of_text_string( t, size, spacing ) = ( width_of_text_string_num_length(len(t), size, spacing) );

function cylinder_center_adjusted_top( height, center )    = (center==true) ? height/2 : height ;
function cylinder_center_adjusted_bottom( height, center ) = (center==true) ? height/2 : 0 ;


//Angle that measures width of letters on perimeter of a circle (and sphere and cylinder)
function rotation_for_character(size, spacing, r, rotate = 0)
 = ( width_of_text_char( size, spacing ) /(internal_pi2*r))*360*(1-abs(rotate)/90);


//Rotate 1/2 width of text if centering	
//One less -- if we have a single char we are already centred..
function rotation_for_center_text_string( t, size, spacing,r,rotate,center)
	= (center) ? (width_of_text_string_num_length( len(t)-1, size, spacing )/2/(internal_pi2*r)*360) : 0 ;

//Rotate according to rotate and if centred text also 1/2 width of text
function rotation_for_center_text_string_and_rotate( t, size, spacing,r,rotate,center)
	= ((center) ? (width_of_text_string( t, size, spacing )/2/(internal_pi2*r)*360) : 1) * (1-abs(rotate)/90);


//---- Text on Object Functions ----
//Text on the top or side of a cylinder.
//Supports writing on normal and slanty cylinders
//cylinder(h,r,center)
//cylinder(h,r1,r2,center)
module text_on_cylinder(t=default_t,
                        //Object-specific                        
                        locn_vec = [0,0,0],
                        r,r1,r2,h,
                        face             = default_cylinder_face,
                        updown           = default_cylinder_updown,
                        rotate           = default_rotate,
                        eastwest         = default_circle_eastwest,
                        middle           = default_circle_middle,
                        ccw              = default_circle_ccw,
                        cylinder_center  = false, //if the cylinder object we are writing on is center==true
                        //TODO: add rounded
                        
                        //All objects
                        extrusion_height = default_extrusion_height,
                        center           = default_center,
                        //All objects -- arguments as for text()
                        font             = undef,
                        size             = default_size,
                        direction        = undef,
                        halign           = undef,
                        valign           = undef,
                        language         = undef,
                        script           = undef,
                        spacing          = default_spacing
){
//    echo (str("text_on_cylinder:There are " ,len(t) ," letters in t" , t));
//    echo (str("text_on_cylinder:","h" , h));
//    echo (str("text_on_cylinder:","r=" , r));
//    echo (str("text_on_cylinder:","r1=" , r1));
//    echo (str("text_on_cylinder:","r2=" , r2));

    if((halign!=undef) || (halign!=undef))
    {
        echo (str("text_on_cylinder:","WARNING " , "halign and valign are NOT supported."));
    }

	rtl_sign = (direction=="rtl") ? -1 : 1;
	if ((face=="top")||(face=="bottom") ){
		//Work on a circle
		locn_offset_vec = (face=="top" ) ? [0,0,cylinder_center_adjusted_top(h,cylinder_center)] : [0,0,cylinder_center_adjusted_bottom(h,cylinder_center)] ;
		rotation_angle = (face=="top" ) ? 0 : 180 ;
		int_radius =  (r==undef) ? ((face=="top" ) ? r2 : r1 ) : r;  //Use the top/bottom radius for slanty-cylinders
			rotate(rotation_angle,[1,0,0])
			text_on_circle(t,locn_vec+locn_offset_vec,r=int_radius-size,
				font=font,size=size,
				spacing=spacing,direction=direction,language=language,script=script,halign=halign,valign=valign,
				extrusion_height=extrusion_height,
				rotate=rotate,
				eastwest=eastwest,middle=middle,ccw=ccw);
	}else{
		if((middle!=undef) && (middle!=default_circle_middle))
		{
			//TODO: Which others?
			//TODO: Which side things aren't supported on the circle
			echo (str("text_on_cylinder:","WARNING " , "middle NOT supported for the SIDE of a cylinder."));
		}
		//Work on the side
		locn_offset_vec =  (cylinder_center==true) ? [0,0,0] : [0,0,h/2]; 
		rotate(-rtl_sign * rotation_for_center_text_string_and_rotate(t, size, spacing,r,rotate,center), [0,0,1])
		translate(locn_vec+locn_offset_vec)
		__internal_text_on_cylinder_side(t,locn_vec,r=r,h=h,r1=r1,r2=r2,
			cylinder_center=cylinder_center,
			center=center,
			font=font,size=size,
			spacing=spacing,direction=direction,language=language,script=script,halign=halign,valign=valign,
			extrusion_height=extrusion_height,
			rotate=rotate,face=face,updown=updown,
			eastwest=eastwest);
	}
}

//circle(r)
module text_on_circle(t=default_t,
                      //Object-specific
                      locn_vec = [0,0,0],
                      r,
                      eastwest = default_circle_eastwest,
                      middle = default_circle_middle,
                      ccw = default_circle_ccw,

                      //All objects                      
                      extrusion_height = default_extrusion_height,
                      rotate = default_rotate,
                      center = default_center,
                      
                      //All objects -- arguments as for text()
                      font             = undef,
                      size             = default_size,
                      direction        = undef,
                      halign           = undef,
                      valign           = undef,
                      language         = undef,
                      script           = undef,
                      spacing          = default_spacing
){
//    echo (str("text_on_circle:","There are " ,len(t) ," letters in t" , t));
//    echo (str("text_on_circle:","rotate=" , rotate));
//    echo (str("text_on_circle:","eastwest=" , eastwest));

    if((halign!=undef) || (halign!=undef))
    {
        echo (str("text_on_circle:","WARNING " , "halign and valign are NOT supported."));
    }

	ccw_sign = (ccw==true) ? 1 : -1;
	rtl_sign = (direction=="rtl") ? -1 : 1;
    ttb_btt_inaction = (direction=="ttb" || direction=="btt") ? 0 : 1;
	rotate_z_outer =  -rotate + ccw_sign*eastwest;
	rotate_z_inner = -rtl_sign * ccw_sign * ttb_btt_inaction * rotation_for_center_text_string( t, size, spacing, r-middle, rotate, center);
	rotate( rotate_z_outer, [0,0,1] )
	rotate( rotate_z_inner, [0,0,1] )
	translate(locn_vec)
	for (l=[0:len(t)-1]){
		//TTB/BTT means no per letter rotation
		rotate_z_inner2 = -ccw_sign * 90 + ttb_btt_inaction*rtl_sign*ccw_sign*l*rotation_for_character(size, spacing, r-middle, rotate=0);   //Bottom out=-270+r
		//TTB means we go toward center, BTT means away
		vert_x_offset = (direction=="ttb" || direction=="btt") ?  (l * size * ((direction=="btt") ? -1 : 1)) :  0;
		rotate( rotate_z_inner2, [0,0,1] )
		translate([r - middle - vert_x_offset,0,0])
		rotate(-ccw_sign*270,[0,0,1])  // flip text (botom out = -270)
		text_extrude(t[l],center=true,
			font=font,size=size,
			rotate=undef,
			spacing=spacing,
			direction=undef, //We don't pass direction ( misaligns inside text() ). TODO: Investigate why
			language=language,script=script,halign=halign,valign=valign,
			extrusion_height=extrusion_height );
	}
}

//Only expected to be called from another function. No defaults as expected to be done in parent.
//NOTE: This is hacked. Requires more mathematics than I feel like to do properly today....
//TODO: Refactor the two operations - side of normal and slanty
//No default checks in this funciton -- done in parent
module __internal_text_on_cylinder_side(t=default_t,
                      //Object-specific
                      locn_vec = [0,0,0],
                      r,r1,r2,h,
                      cylinder_center,
                      
                      //All objects
                      extrusion_height = default_extrusion_height,
                      center           = undef,
                      rotate           = default_rotate,
                      
                      //All objects -- arguments as for text()
                      font             = undef,
                      size             = default_size,
                      direction        = undef,
                      halign           = undef, //Overridden
                      valign           = undef,
                      language         = undef,
                      script           = undef,
                      spacing          = default_spacing
)
{
//    echo (str("__internal_text_on_cylinder_side:There are " ,len(t) ," letters in t" , t));
//    echo (str("__internal_text_on_cylinder_side:","h=" , h));
//    echo (str("__internal_text_on_cylinder_side:","r=" , r));
//    echo (str("__internal_text_on_cylinder_side:","r1=" , r1));
//    echo (str("__internal_text_on_cylinder_side:","r2=" , r2));
//    echo (str("__internal_text_on_cylinder_side:","direction=" , direction));
    
    if((halign!=undef) || (halign!=undef))
    {
        echo (str("text_on_cylinder:","WARNING " , "halign and valign are NOT supported."));
    }

    wid = width_of_text_char( size, spacing ); //TODO: refactor this out?

    function calc_radius_at_height_offset(r1,r2,h_total,h_offset) = ( r1 + ((r2-r1) * (h_total-h_offset)/h_total) );
    
  	//Has to factor in up/downedness
    //Starts at middle height then height displacement is reduced under rotation and by the slope of the uneven radii
    function calc_height_offset_at_length(r1,r2,h,length,rotate, updown) = ( h/2 - updown + length * rotate/90 * cos( atan( (r2-r1)/h ) )  );

    function calc_radius_at_length(r1,r2,h,length,rotate,updown) = ( calc_radius_at_height_offset(r1,r2,h,calc_height_offset_at_length(r1,r2,h,length,rotate,updown)));
    
    if(r==undef)
    {
        //Slanty-cylinder (truncated cone) warnings
        if((direction=="btt") || (direction=="ttb"))
        {
            //TODO: After the issues are resolved refactoring should give this pretty easily
            echo (str("text_on_cylinder:","WARNING" , " - Slanty-cylinders definitely don't directions TTB or BTT on sides yet. Setting direction to ltr."));    
        }
        if(center==true)
        {
            echo (str("text_on_cylinder:","WARNING" , " - Slanty-cylinders don't support centering yet. Setting center to false. You can adjust updown and eastwest and achieve most of what you are after...."));    
        }
    }

    r1  = (r1!=undef) ? r1 : r;
    r2  = (r2!=undef) ? r2 : r;
    //NOTE: r is not used after here. We operate on generalised slanty cone (r1 and r2)
    
  	//TODO: Look at changing this to extrusion_height_center
	//and renaming the other as text_center
	rr1 = (center) ? r1-extrusion_height/2 : r1;
	rr2 = (center) ? r2-extrusion_height/2 : r2;
	
    ccenter  = (r!=undef) ? center : false; //We don't do (text) centering for the slanty cones/helical paths (yet? ever?). Needs to do quite a few offset calcs.
    ddirection   = ((r==undef) && ((direction=="ttb")||(direction=="btt"))) ? "ltr" : direction; //We don't do ttb or btt directions on slanty
    rtl_sign = (ddirection=="rtl") ? -1 : 1;

        //This code takes care of slanty cylinders and "normal" cylinders
        translate([0,0,updown])
        rotate(eastwest,[0,0,1])
        for (l=[0:len(t)-1]){
            //TODO: TTB and BTT need to have a different concept of path/length than this for RTL/LTR
   	        //width_of_... is half a char too long -- add 0.5 (counting from zero)
            length_to_center_of_char = width_of_text_string_num_length(l+0.5,size,spacing);
            radius_here = calc_radius_at_length(rr1,rr2,h, length_to_center_of_char, rotate, updown);
            //Rotating into position and tangentially to surface -- Don't rotate per character for ttb/btt
            //-90 is to get centering at origin
		    rotate_z_inner  = -90 + rtl_sign * rotation_for_character(size, spacing, ( radius_here ), rotate) * ((ddirection=="ttb" || ddirection=="btt") ?  0 : l);
	        rotate(rotate_z_inner,[0,0,1])
			{
	        //Positioning - based on (somewhat innacurate) string length
		    //Offset per character to go up/down the side in ttb/btt -- TTB down, BTT up
		    vert_z_char_offset = (ddirection=="ttb" || ddirection=="btt") ?  (l * size * ((ddirection=="ttb") ? -1 : 1 )) :  0 ;
		    //Only if RTL/LTR and if center -- center the text (starts off in a more visually appealing location)
		    vert_z_half_text_offset_tmp = (len(t)-1)/2 * (rotate/90*wid);
		    vert_z_half_text_offset =  ((ddirection=="ttb" || ddirection=="btt") || (ccenter==false)) ? 0 : vert_z_half_text_offset_tmp;
            translate([ radius_here , 0, vert_z_char_offset - l * ((rotate)/90*wid) + vert_z_half_text_offset])

	        //Flip to tangent on the sloping side (without respecting rotation impact on the tangent -- rotate seems a little off. TODO: Investigate).
	        rotate( atan( (rr2-rr1)/h ) , [0,1,0])
	        //Flip onto face of "normal" cylinder
	        rotate(90,[1,0,0])
	        rotate(90,[0,1,0])

    	    //Modify the offset of the baselined text to center
            translate([0,(ccenter) ? -size/2 : 0,0])
	        
	        text_extrude(t[l],
	            center=false,
	            rotate=rotate,
	            font=font,size=size,
	            spacing=spacing,
	            direction=undef, //We don't pass direction ( misaligns inside text() ). TODO: Investigate why
	            language=language,script=script,
	            halign="center", //This can be relaxed eventually
                valign="baseline", //Need this to keep all letters on the same line (could also support top -- otherw will make
	            extrusion_height=extrusion_height
	            );
			}
        }
}

//sphere(r)
//NB: Iterates through characters/glyphs and presents them individually (but supports actions across the entire string still)
//supports all features of text() except: halign and valign
module text_on_sphere(t=default_t,
                      //Object-specific
                      locn_vec = [0,0,0],
                      r,
                      eastwest         = default_sphere_eastwest,
                      northsouth       = default_sphere_northsouth,
                      rotate           = default_rotate,
                      spin             = default_sphere_spin,
                      rounded          = default_sphere_rounded,
                      //All objects
                      extrusion_height = default_extrusion_height,
                      center           = default_center, //center = false doesn't really even make sense to do (IMHO)
                      scale  = default_scale,
                      //All objects -- arguments as for text()
                      font             = undef,
                      size             = default_size,
                      direction        = undef,
                      halign           = undef, //Not supported - only here to enable a warning
                      valign           = undef, //Not supported - only here to enable a warning
                      language         = undef,
                      script           = undef,
                      spacing          = default_spacing
){
    //echo ("text_on_sphere:There are " ,len(t) ," letters in t" , t);

    if((halign!=undef) || (halign!=undef))
    {
        echo (str("text_on_sphere:","WARNING " , "halign and valign are NOT supported (functionality used in centering)."));
    }

    //TODO: refactor this?
	rtl_sign = (direction=="rtl") ? -1 : 1;
	
	//TODO: Look at changing this to extrusion_height_center
	//and renaming the other as text_center
	//If we are centered - we sink the radius by half the
	//extrusion height to draw "just below the surface"
	rr = (center) ? r-extrusion_height/2 : r ;
	
	rotate(eastwest,[0,0,1])
	rotate(-northsouth,[1,0,0])
	rotate(spin,[0,1,0])
	{
	//This tries to center the text (for RTL text).
    ttb_btt_inaction = (direction=="ttb" || direction=="btt") ? 0 : 1;
	rotate( -rtl_sign * ttb_btt_inaction * rotation_for_center_text_string(t, size, spacing, rr, rotate, center), [0,0,1])
	{
	    translate(locn_vec)
		if ( rounded == false ){
			__internal_text_on_sphere_helper(t=t,r=rr,
	    		rotate=rotate,
	    		center=center,
	    		scale=scale,
	            font=font,size=size,
                spacing=spacing,
                direction=direction,
                language=language,script=script,halign=halign,valign=valign,
                extrusion_height=extrusion_height
			);
		}else{
		    //If rounding then clip the text inside an inner sphere and outer sphere
			intersection()
			{
			__internal_text_on_sphere_helper(t=t,r=rr,
        		rotate=rotate,
        		center=center,
        		scale=scale,
                font=font,size=size,
                spacing=spacing,
                direction=direction,
                language=language,script=script,halign=halign,valign=valign,
                extrusion_height=extrusion_height*2 //Make it proud to clip it off.
		    );

            //Shell - bounding inner and outer
			difference()
			{   //rounded outside
				sphere(rr+extrusion_height);
				// rounded inside for indented text
			    sphere( rr  );
			}

		    }
		}
		}
	}
}

//internal function -- don't call directly
//No default checks in this funciton -- done in parent
module __internal_text_on_sphere_helper(t=default_t,
                      //Object-specific
                      r,
                      //All objects
                      extrusion_height = default_extrusion_height,
                      center           = default_center,
                      scale  = default_scale,
                      //All objects -- arguments as for text()
                      font             = undef,
                      size             = default_size,
                      direction        = undef,
                      //halign           = undef,
                      //valign           = undef,
                      language         = undef,
                      script           = undef,
                      spacing          = default_spacing
)
{
    rtl_sign = (direction=="rtl") ? -1 : 1;
    ttb_btt_inaction = (direction=="ttb" || direction=="btt") ? 0 : 1;
    ttb_btt_action   = (direction=="ttb" || direction=="btt") ? 1 : 0;
    
    for (l=[0:len(t)-1]){
	    rotate_z_inner   = -90 + rtl_sign * ttb_btt_inaction * l * rotation_for_character(size, spacing, r, 0);
	    
        rotate( rotate_z_inner, [0,0,1] )
		{
        translate_sign   = (direction=="ttb" || direction=="btt") ? ((direction=="btt") ? 1 : -1)  : 0 ;
        //translate_effect = (direction=="ttb" || direction=="btt") ? 1  :  0 ;
        //Translate letter to be located on the sphere in up/down direction when we are doing TTB and BTT
	    translate(r * [cos(0 + ttb_btt_action * rotation_for_character(size, spacing, r, rotate) * l ), 0, translate_sign * ttb_btt_action * sin(0 +  rotation_for_character(size, spacing, r, rotate) * l ) ])
        //Rotate letter to be tangential to the new part of the sphere when we are doing TTB and BTT
	    rotate(-90 * translate_sign * (0 + ttb_btt_action * rotation_for_character(size, spacing, r, rotate) * l )/90 , [0,1,0])
        //Flip character into position to be flush against sphere
	    rotate(90,[1,0,0])
	    rotate(90,[0,1,0])
	    
	    //Modify the offset of the baselined text to center
	    translate([0,(center) ? -size/2 : 0 ,0])
	    
	    text_extrude(t[l],
	        center=false,
	        rotate=rotate,
	        scale=scale,
	        font=font,
	        size=size,
            spacing=spacing,
            direction=undef, //We don't pass direction ( misaligns inside text() ). TODO: Investigate why
            language=language,script=script,
            halign="center", //This can be relaxed eventually
            valign="baseline", //Need this to keep all letters on the same line (could also support top -- otherw will make wonky letters)
            extrusion_height=extrusion_height );
		}
    }
}



//cube(size)
//cube([width,h,depth])
//NB: cube_size is used instead of size (the name size is used in the text module)
//NB: Passes through text as strings -- supports all features of text()
module text_on_cube(  t=default_t,
                      //Object-specific
                      cube_size, //number or 3-vector
                      face      = default_cube_face,
                      rightleft = default_cube_rightleft,
                      updown    = default_cube_updown,
                      //All objects
                      locn_vec = [0,0,0],
                      extrusion_height = default_extrusion_height,
                      center = undef,
                      rotate = default_rotate,
                      scale  = default_scale,
                      //All objects -- arguments as for text()
                      font             = undef,
                      size             = default_size,
                      direction        = undef,
                      halign           = undef,
                      valign           = undef,
                      language         = undef,
                      script           = undef,
                      spacing          = default_spacing
){
    //echo (str("text_on_cube:","There are " ,len(t) ," letters in t" , t));
    //echo (str("text_on_cube:","cube_size" , cube_size));
    
    if((halign!=undef) || (halign!=undef))
    {
        echo (str("text_on_cube:","WARNING " , "halign and valign are NOT supported."));
    }

    int_cube_size = (str(cube_size)[0] != "[") ? [cube_size,cube_size,cube_size] : cube_size;
    rotate_x = ( (face=="front") || (face=="back") || (face=="left") || (face=="right") ) ? 90
				: ((face=="bottom") ? 180 : 0) ; //Top is zero
	rotate_y = ( (face=="back") || (face=="left") || (face=="right") ) ? (face=="back") ? 180 : ((face=="left") ? -90 : 90) //Right is 90
				: 0 ; //Top, bottom, front are zero
	locn_vec_offset =
	        (face=="front") ?             [+rightleft,   -int_cube_size[1]/2, +updown]
	        :((face=="back")?             [+rightleft,   +int_cube_size[1]/2, +updown]
	            : ((face=="left")?         [-int_cube_size[0]/2, +rightleft,   +updown]
	                : ((face=="right")?    [+int_cube_size[0]/2, +rightleft,   +updown]
	                    : ((face=="top")?  [+rightleft,   +updown,             +int_cube_size[2]/2]
	                        :              [+rightleft,   -updown,             -int_cube_size[2]/2]
							)))); //bottom
							
		translate(locn_vec + locn_vec_offset)
		rotate(rotate_x,[1,0,0])
		rotate(rotate_y,[0,1,0])  // rotate around the y axis (z before rotation)
		text_extrude(t,
		    center=center,
		    rotate=rotate,
		    scale=scale,
		    font=font,
		    size=size,
		    spacing=spacing,
		    direction=direction, //Does this misalign inside text()? the individual character modules do.
		    language=language,
		    script=script,
		    halign=halign,
		    valign=valign,
		    extrusion_height=extrusion_height );
}

function default_if_undef(val, default_val) = (val!=undef) ? val : default_val ;

//Print a single character or a string at the desired extrusion height
//Passes on values to text() that are passed in
//TODO: Add x,y,z rotations get text facing the right way from the start)
module text_extrude( t=default_t,
                     extrusion_height = default_extrusion_height,
                     center = default_center, //Fudgy. YMMV. //TODO:center_extrusion, or extrusion offset??
                     rotate = default_rotate,
                     scale  = default_scale, //For scaling by different on axes (for widening etc)
                     //Following are test() params (in addition to t=)
                     font             = default_font,
                     size             = default_size,
                     direction        = undef,
                     halign           = undef,
                     valign           = undef,
                     language         = undef,
                     script           = undef,
                     spacing          = default_spacing
)
{
    //echo (str("text_extrude:","There are " ,len(t) ," letters in text" , t));
    //echo (str("text_extrude:","extrusion_height=" , extrusion_height));
    
    if(center==true)
    {
        if((halign!=undef) || (valign!=undef))
        {
            echo (str("text_extrude:","WARNING " , "When center is true, then halign and valign are NOT supported."));
        }
    }
    
    //As arguments are explicitly set as undef (from higher functions) as they come down (they don't get defaults in this function as they are set as something)
    //we need to check and replace any that we don't want to be undef
    t                 = default_if_undef(t,default_t);
    font              = default_if_undef(font,default_font);
    extrusion_height  = default_if_undef(extrusion_height,default_extrusion_height);
    center            = default_if_undef(center,default_center);
    rotate            = default_if_undef(rotate,default_rotate);
    spacing           = default_if_undef(spacing,default_spacing);
    size              = default_if_undef(size,default_size);
    
    halign            = (center) ? "center" : halign ;
    valign            = (center) ? "center" : valign ;
    extrusion_center  = (center) ? true : false ;
	
	scale( scale )
    rotate(rotate,[0,0,-1]) //TODO: Do we want to make this so that the entire vector can be set?
	{
	    linear_extrude(height=extrusion_height,convexity=10,center=extrusion_center)
        text(text=t, size = size,
            $fn = 40,
            font = font, direction = direction, spacing = spacing,
            halign = halign,
            valign = valign,
            language=language, script=script);
	}
}