Adding custom fonts to Cairo

[Bobflip]

I'm wanting to change the font used within Cairo, and have been examining the various font face functions but am getting a bit lost and not sure where to begin. Also, is it possible to import a TrueType font or is it all FreeType?

[earlevel]

Originally Posted by Bobflip

I'm wanting to change the font used within Cairo, and have been examining the various font face functions but am getting a bit lost and not sure where to begin. Also, is it possible to import a TrueType font or is it all FreeType?

Don't know anything about it, but since FreeType supports TrueType, that should be the answer to the second question.

[Bobflip]

Ah, well that's a start, cheers!

[Youlean]

Look at ycairo_text class if you are using my framework... The best way for using is to create global font in plugin constructor.

[MSK]

This is how I set a global font using Youlean's branch.

In the plugin constructor:

   // Youlean's Cairo base
  ycairo_base * base = GetYCAIRO();
  
  // Create base font - this is used in all ycairo_text instances throughout
  base -> create_global_font_from_path("/Library/Fonts/Futura.ttc");

Then in a control you'd want some thinglike this:

 
// In the control constructor
ycairo_text * yText = new ycairo_text(ycairo_base);

// In the Draw() method
yText -> ycairo_show_text(cr, textChar, textSize, IRECT);

Hope that helps!
MSK

[Youlean]

Originally Posted by MSK

This is how I set a global font using Youlean's branch.

In the plugin constructor:

   // Youlean's Cairo base
  ycairo_base * base = GetYCAIRO();
  
  // Create base font - this is used in all ycairo_text instances throughout
  base -> create_global_font_from_path("/Library/Fonts/Futura.ttc");

Then in a control you'd want some thinglike this:

 
// In the control constructor
ycairo_text * yText = new ycairo_text(ycairo_base);

// In the Draw() method
yText -> ycairo_show_text(cr, textChar, textSize, IRECT);

Hope that helps!
MSK

This is how I am using it:

class SomeControl: public IControl, ycairo_gui, ycairo_text
{
public:
	SomeControl(IPlugBase* pPlug, ycairo_base *ycairo_base, IRECT pR)
		: IControl(pPlug, pR), ycairo_gui(ycairo_base, this), ycairo_text(ycairo_base) {}
}

BTW you should never create object with new if you don't really need to. If you want to create object just use ycairo_text textObject;

[Youlean]

Creating global font from path is also not ideal. It would be best to ship font with your binary. To do that use:

resource.h

// Font declaration ---------------------------------------------------------------------
#define FONT_FILE 256  //Must be greater than 255, it should be declared once
#define FONT_ID 102 //Unique ID
#define FONT_PATH "resources/SomeFont.ttf"
//-------------------------------------------------------------------------------------

*.rc

#include "resource.h"

FONT_ID             FONT_FILE             FONT_PATH

constructor

GetYCAIRO()->create_global_font_from_memory(FONT_ID, FONT_FILE, FONT_PATH);

[Bobflip]

Thanks everyone for the advice, I'll experiment this weekend, and I certainly plan to ship the font within the binaries.

Up to now I've been using cairo_text_path to draw text, is this compatible with the techniques described, or will I have to do a hefty session of rewriting?

[Youlean]

Originally Posted by Bobflip

Thanks everyone for the advice, I'll experiment this weekend, and I certainly plan to ship the font within the binaries.

Up to now I've been using cairo_text_path to draw text, is this compatible with the techniques described, or will I have to do a hefty session of rewriting?

Filling text path is very expensive on CPU (up to 1000% CPU increase), so you should switch to my methods (ycairo_show_text).

[Bobflip]

Blimey, hahaha! Ok, definitely sorting that this weekend.

Although that said, I've been using the paths to create an outline around the text like this:

	// Outline text
	cairo_move_to(cr, mDrawRECT.L + x, mDrawRECT.T + y);
	cairo_text_path(cr, mStr.Get());
	cairo_fill_preserve(cr);
	cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
	cairo_set_line_width(cr, 2.56);
	cairo_stroke(cr);

	// Overlaid non-outline text
	cairo_move_to(cr, mDrawRECT.L + x, mDrawRECT.T + y);
	cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
	cairo_text_path(cr, mStr.Get());
	cairo_fill_preserve(cr);
	cairo_set_line_width(cr, 0.0);
	cairo_stroke(cr);

I can't see a way of doing this directly with ycairo_show_text, although maybe it's possible with ycairo_drop_shadow_stroke?

[Youlean]

Originally Posted by Bobflip

I can't see a way of doing this directly with ycairo_show_text, although maybe it's possible with ycairo_drop_shadow_stroke?

No drop shadow will be even more taxing on CPU. IF you want to outline text you need to use paths. you should look inside ycairo_show_text method to see how to create path with freetype.

[Bobflip]

That's the thing, I had a look in there but couldn't work out how to get a path from it, it's a bit over my head at this point.

void ycairo_text::ycairo_show_text(cairo_t * cr, const char * text, double size, IColor color, IRECT rect, ycairo_text_w_aligement w_aligement, ycairo_text_h_aligement h_aligement)

{
	cairo_set_source_rgba(cr, color.R / 255.0, color.G / 255.0, color.B / 255.0, color.A / 255.0);

	ycairo_initialize_font_face(cr);
	cairo_set_font_size(cr, size);
	ycairo_set_text(cr, text);
	ycairo_set_text_position(cr, rect, w_aligement, h_aligement);

	//// Adding subpixel rendering improves rendering speed by 10% on my system
	//cairo_font_options_t *options;
	//cairo_get_font_options(cr, options);

	//cairo_font_options_set_antialias(options, CAIRO_ANTIALIAS_SUBPIXEL);
	//cairo_set_font_options(cr, options);
	//// -----------------------------------------------------------------------

	cairo_show_text(cr, text);

	ycairo_destroy_font_face();
}

void ycairo_text::ycairo_show_text(cairo_t * cr)
{
	cairo_show_text(cr, draw_text);
}

[Youlean]

[QUOTE=Bobflip;1898128]That's the thing, I had a look in there but couldn't work out how to get a path from it, it's a bit over my head at this point.

Read https://www.cairographics.org/manual/index.html


Anyways use cairo_text_path instead of cairo_show_text

[Bobflip]

I think that may have been where I learnt how to do it initially! The tutorials there were really handy while learning my way around Cairo.

I'm already using cairo_text_path in the code I posted above (post #10), I guess I could speed things up by using ycairo_show_text for the non-outline text and just use the path for the outline.

[Youlean]

Originally Posted by Bobflip

I think that may have been where I learnt how to do it initially! The tutorials there were really handy while learning my way around Cairo.

I'm already using cairo_text_path in the code I posted above (post #10), I guess I could speed things up by using ycairo_show_text for the non-outline text and just use the path for the outline.

Indeed but you will also speed up things if you use freetype to create font instead of cairo fonts.

[Bobflip]

Ok, thanks, will get that on the to-do list.

Having trouble creating the font still though, so I've pasted the code into the relevant bits of a fresh IPlugEffect, dropped a font into resources and dragged it into XCode's resources, and updated FONT_PATH to match, but on both Windows and Mac it bombs out with a Bad Access error at if (global_font) in create_global_font_from_memory.

[Bobflip]

Actually, wait. I put it into IPlugEffectCairoGraphics (where I was originally doing the font testing!) and it loads ok, but it wasn't working in my plugin yet. Just going to get the font loading working in IPlugEffectCairoGraphics for now and then try and extrapolate it to mine!

[Bobflip]

Ok yeah, got it sorted in both the example and in my own code! Not been able to get the cairo path text to line up with the ycairo text, but this seems to do the trick nicely. Thanks for the pointers.

		ycairo_prepare_draw();
		ycairo_initialize_font_face(cr);
		cairo_set_font_size(cr, 12);
		
		cairo_set_line_join(cr, CAIRO_LINE_JOIN_ROUND);
		cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
		
		// Find coordinates to centre text
		cairo_text_extents_t extents;
		cairo_text_extents(cr, outputString, &extents);
		double x = (mDrawRECT.W() / 2) - (extents.width / 2 + extents.x_bearing);
		cairo_text_extents (cr, "0", &extents); // This gets the vertical centre but ignores the tails on a lower case 'p', for example
		double y = (mDrawRECT.H() / 2) - (extents.height / 2 + extents.y_bearing);

		// Round off the coordinates to prevent blurring.
		x = floor(x);
		y = floor(y);

		// Outline text
		cairo_move_to(cr, mDrawRECT.L + x, mDrawRECT.T + y);
		cairo_text_path(cr, outputString);
		cairo_fill_preserve(cr);
		cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
		cairo_set_line_width(cr, 2.56);
		cairo_stroke(cr);

		// Overlaid non-outline text
		cairo_move_to(cr, mDrawRECT.L + x, mDrawRECT.T + y);
		cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
		cairo_text_path(cr, outputString);
		cairo_fill_preserve(cr);
		cairo_set_line_width(cr, 0.0);
		cairo_stroke(cr);


		ycairo_draw();
		return true;