relying on cairo recording surface for extents and preset bitmap at load time, work in progress

include/freetype/internal/internal.h

@@ -37,6 +37,7 @@
 #define FT_INTERNAL_SERVICE_H             <freetype/internal/ftserv.h>
 #define FT_INTERNAL_RFORK_H               <freetype/internal/ftrfork.h>
 #define FT_INTERNAL_VALIDATE_H            <freetype/internal/ftvalid.h>
+#define FT_INTERNAL_SVG_INTERFACE_H       <freetype/internal/svginterface.h>
 
 #define FT_INTERNAL_TRUETYPE_TYPES_H      <freetype/internal/tttypes.h>
 #define FT_INTERNAL_TYPE1_TYPES_H         <freetype/internal/t1types.h>

include/freetype/internal/svginterface.h

@@ -0,0 +1,42 @@
+/****************************************************************************
+ *
+ * svginterface.h
+ *
+ *   Exposes the interface of ot-svg module
+ *
+ * Copyright (C) 1996-2019 by
+ * David Turner, Robert Wilhelm, Werner Lemberg and Moazin Khatti.
+ *
+ * This file is part of the FreeType project, and may only be used,
+ * modified, and distributed under the terms of the FreeType project
+ * license, LICENSE.TXT.  By continuing to use, modify, or distribute
+ * this file you indicate that you have read the license and
+ * understand and accept it fully.
+ *
+ */
+
+
+#ifndef SVGINTERFACE_H
+#define SVGINTERFACE_H
+
+#include <ft2build.h>
+#include FT_SVG_RENDER_H
+
+
+FT_BEGIN_HEADER
+
+  typedef FT_Error
+  (*Preset_Bitmap_Func)( FT_Module     module,
+                         FT_GlyphSlot  slot,
+                         FT_Bool       cache );
+
+  typedef struct SVG_Interface_
+  {
+    Preset_Bitmap_Func  preset_slot;
+  } SVG_Interface;
+
+  typedef SVG_Interface*  SVG_Service;
+
+FT_END_HEADER
+
+#endif

include/freetype/svgrender.h

@@ -82,44 +82,32 @@ FT_BEGIN_HEADER
    *   slot ::
    *     The whole glyph slot object.
    *
-   *   outline_bbox ::
-   *     The bounding box of the glyph in font units.  So that the renderer
-   *     may not need to calculate it again.
-   *
    * @return:
    *   FreeType error code.  0 means success.
    */
 
   typedef FT_Error
-  (*SVG_Lib_Render_Func)( FT_GlyphSlot  slot,
-                          FT_BBox       outline_bbox);
+  (*SVG_Lib_Render_Func)( FT_GlyphSlot  slot );
 
   /**************************************************************************
    *
    * @functype:
-   *   SVG_Lib_Get_Buffer_Size_Func
+   *   SVG_Lib_Preset_Slot_Func
    *
    * @description:
-   *   A callback which is called to get the size of the image buffer needed.
-   *   This buffer will ultimately be populated by `SVG_Lib_Render_Func`
-   *   hook.
+   *   A callback which is to preset the glyphslot.
    *
    * @input:
    *   slot ::
-   *     The glyph slot which has the SVG document loaded as well as other
-   *     info.
-   *
-   *   bbox ::
-   *     The bbox in font units. This is required for the rendering port to
-   *     predict the final size of the image buffer.
+   *     The glyph slot which has the SVG document loaded.
    *
    * @return:
-   *   Size of the state structure in bytes.
+   *   FreeType error code.  0 means success.
    */
 
-  typedef FT_ULong
-  (*SVG_Lib_Get_Buffer_Size_Func)( FT_GlyphSlot  slot,
-                                   FT_BBox       bbox );
+  typedef FT_Error
+  (*SVG_Lib_Preset_Slot_Func)( FT_GlyphSlot  slot, FT_Bool  cache);
+
 
   typedef struct SVG_RendererHooks_
   {
@@ -128,9 +116,10 @@ FT_BEGIN_HEADER
     SVG_Lib_Free_Func    free_svg;
     SVG_Lib_Render_Func  render_svg;
 
-    SVG_Lib_Get_Buffer_Size_Func  get_buffer_size;
+    SVG_Lib_Preset_Slot_Func  preset_slot;
   } SVG_RendererHooks;
 
+
   /**************************************************************************
    *
    * @struct:

src/base/ftobjs.c

@@ -28,6 +28,7 @@
 #include FT_INTERNAL_STREAM_H
 #include FT_INTERNAL_SFNT_H            /* for SFNT_Load_Table_Func */
 #include FT_INTERNAL_POSTSCRIPT_AUX_H  /* for PS_Driver            */
+#include FT_INTERNAL_SVG_INTERFACE_H
 
 #include FT_TRUETYPE_TABLES_H
 #include FT_TRUETYPE_TAGS_H
@@ -363,6 +364,7 @@
   {
     FT_Outline*  outline = &slot->outline;
     FT_Bitmap*   bitmap  = &slot->bitmap;
+    FT_Module    module;
 
     FT_Pixel_Mode  pixel_mode;
 
@@ -374,7 +376,17 @@
 
 
     if ( slot->format != FT_GLYPH_FORMAT_OUTLINE )
-      return 1;
+    {
+      if ( slot->format == FT_GLYPH_FORMAT_SVG )
+      {
+        module = FT_Get_Module(slot->library, "ot-svg" );
+        SVG_Service svg_service = module->clazz->module_interface;
+
+        svg_service->preset_slot( module, slot, FALSE );
+      }
+      else
+        return 1;
+    }
 
     if ( origin )
     {

src/svg/ftsvg.c

@@ -19,6 +19,7 @@
 #include FT_INTERNAL_DEBUG_H
 #include FT_SERVICE_PROPERTIES_H
 #include FT_SVG_RENDER_H
+#include FT_INTERNAL_SVG_INTERFACE_H
 #include FT_BBOX_H
 
 #ifdef FT_CONFIG_OPTION_DEFAULT_SVG
@@ -43,7 +44,7 @@
     svg_module->hooks.init_svg = (SVG_Lib_Init_Func)rsvg_port_init;
     svg_module->hooks.free_svg = (SVG_Lib_Free_Func)rsvg_port_free;
     svg_module->hooks.render_svg = (SVG_Lib_Render_Func)rsvg_port_render;
-    svg_module->hooks.get_buffer_size = (SVG_Lib_Get_Buffer_Size_Func)rsvg_port_get_buffer_size;
+    svg_module->hooks.preset_slot = (SVG_Lib_Preset_Slot_Func)rsvg_port_preset_slot;
     svg_module->hooks_set = TRUE;
 #else
     FT_TRACE3(( "ft_svg_init: No default hooks set\n" ));
@@ -62,6 +63,23 @@
     svg_module->loaded = FALSE;
   }
 
+  static FT_Error
+  ft_svg_preset_slot( FT_Module     module,
+                      FT_GlyphSlot  slot,
+                      FT_Bool       cache )
+  {
+    SVG_Renderer      svg_renderer = (SVG_Renderer)module;
+    SVG_RendererHooks hooks        = svg_renderer->hooks;
+
+    if ( svg_renderer->hooks_set == FALSE )
+    {
+      FT_TRACE1(( "Hooks are NOT set. Can't render OT-SVG glyphs\n" ));
+      return FT_THROW( Missing_SVG_Hooks );
+    }
+
+    return hooks.preset_slot( slot, cache );
+  }
+
   static FT_Error
   ft_svg_render( FT_Renderer       renderer,
                  FT_GlyphSlot      slot,
@@ -71,7 +89,6 @@
     SVG_Renderer  svg_renderer = (SVG_Renderer)renderer;
     FT_Library    library      = renderer->root.library;
     FT_Memory     memory       = library->memory;
-    FT_BBox       outline_bbox;
     FT_Error      error;
     FT_ULong      size_image_buffer;
 
@@ -90,20 +107,19 @@
       svg_renderer->loaded = TRUE;
     }
 
-    /* Let's calculate the bounding box in font units here */
-    error = FT_Outline_Get_BBox( &slot->outline, &outline_bbox );
-    if( error != FT_Err_Ok )
-      return error;
-
-    size_image_buffer = hooks.get_buffer_size( slot, outline_bbox );
-
-    FT_MEM_ALLOC( slot->bitmap.buffer, size_image_buffer );
+    ft_svg_preset_slot( renderer, slot, TRUE);
+    size_image_buffer = slot->bitmap.pitch * slot->bitmap.rows;
+    FT_MEM_ALLOC( slot->bitmap.buffer, size_image_buffer);
     if ( error )
       return error;
 
-    return hooks.render_svg( slot, outline_bbox );
+    return hooks.render_svg( slot );
   }
 
+  static const SVG_Interface svg_interface = {
+    (Preset_Bitmap_Func)ft_svg_preset_slot
+  };
+
   static FT_Error
   ft_svg_property_set( FT_Module    module,
                        const char*  property_name,
@@ -188,7 +204,7 @@
       "ot-svg",
       0x10000L,
       0x20000L,
-      NULL,                                /* module specific interface */
+      (const void*)&svg_interface,                           /* module specific interface */
       (FT_Module_Constructor)PUT_SVG_MODULE( ft_svg_init ),  /* module_init */
       (FT_Module_Destructor)PUT_SVG_MODULE( ft_svg_done ),   /* module_done */
       PUT_SVG_MODULE( ft_svg_get_interface ),                /* get_interface */