[Yt-svn] yt: Adding new freetype wrapper, to add very simple textual anno...

[hg at spacepope.org]

hg Repository: yt
details:   yt/rev/80139ad4948b
changeset: 3565:80139ad4948b
user:      Matthew Turk <matthewturk at gmail.com>
date:
Wed Dec 01 18:11:40 2010 -0800
description:
Adding new freetype wrapper, to add very simple textual annotations to images.
This will be useful for volume renderings, to avoid having to use matplotlib
and its compositing mechanisms.

It's not currently added in or wrapped; this is just the initial file.  Once I
have figured out and become satisfied with wrapping it nicely and with
compilation information, I'll add it to amr_utils.pyx.

diffstat:

 yt/utilities/_amr_utils/freetype_writer.pyx |  107 ++++++++++++++++++++++++++++
 1 files changed, 107 insertions(+), 0 deletions(-)

diffs (111 lines):

diff -r 04a59a41ef08 -r 80139ad4948b yt/utilities/_amr_utils/freetype_writer.pyx
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/yt/utilities/_amr_utils/freetype_writer.pyx	Wed Dec 01 18:11:40 2010 -0800
@@ -0,0 +1,107 @@
+"""
+A light interface to FreeType2
+
+Author: Matthew Turk <matthewturk at gmail.com>
+Affiliation: UCSD
+Homepage: http://yt.enzotools.org/
+License:
+  Copyright (C) 2010 Matthew Turk.  All Rights Reserved.
+
+  This file is part of yt.
+
+  yt is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+
+import numpy as np
+cimport numpy as np
+cimport cython
+
+cdef int initialized = 0
+
+from stdio cimport fopen, fclose, FILE
+
+cdef extern from "freetype_includes.h":
+    # NOTE that size_t might not be int
+    ctypedef struct FT_Library:
+        pass
+
+    ctypedef struct FT_Bitmap:
+        unsigned char *buffer
+        int width
+        int rows
+
+    ctypedef struct FT_Vector:
+        int x
+        int y
+
+    ctypedef struct FT_GlyphSlotRec:
+        FT_Bitmap bitmap
+        int bitmap_left
+        int bitmap_top
+        FT_Vector advance
+    ctypedef FT_GlyphSlotRec* FT_GlyphSlot
+
+    ctypedef struct FT_FaceRec:
+        FT_GlyphSlot glyph
+    ctypedef FT_FaceRec* FT_Face
+
+    int FT_LOAD_RENDER
+
+    int FT_Init_FreeType( FT_Library *lib)
+    int FT_New_Face(FT_Library library, char* filepathname, long face_index,
+                    FT_Face *aface)
+    int FT_Set_Char_Size(FT_Face face, double width, double height,
+                         unsigned dpi_w, unsigned dpi_h)
+    int FT_Load_Char(FT_Face face, unsigned long char_code, int load_flags)
+
+cdef FT_Library library
+
+def initialize_library():
+    # We do not clear the library from memory.
+    if initialized == 1: return
+    cdef int error = FT_Init_FreeType(&library)
+    if error: raise RuntimeError
+    initialized = 1
+
+def simple_writing(char *fontpath, long face_index, long dpi,
+                   long font_size, char *text,
+                   np.ndarray[np.uint8_t, ndim=3] buffer,
+                   int xpos, int ypos):
+    initialize_library()
+    cdef FT_Face face
+    cdef int error = FT_New_Face(library, fontpath, face_index, &face)
+    if error: raise RuntimeError(error)
+    error = FT_Set_Char_Size(face, 0, font_size * 64, dpi, dpi)
+    if error: raise RuntimeError(error)
+    cdef FT_GlyphSlot slot = face.glyph
+    cdef int n, i, j, c
+    cdef pi = xpos, pj = ypos # Pen locations
+    cdef di, dj # Where we actually draw
+    cdef char tchar
+    cdef int ichar
+    cdef np.uint8_t bb
+    for n in range(len(text)):
+        tchar = text[n]
+        ichar = <int> tchar
+        error = FT_Load_Char(face, ichar, FT_LOAD_RENDER)
+        if error: raise RuntimeError(error)
+        for i in range(slot.bitmap.width):
+            for j in range(slot.bitmap.rows):
+                di = pi + slot.bitmap_left + i
+                dj = pj - slot.bitmap_top + j
+                for c in range(3):
+                    bb = <np.uint8_t> slot.bitmap.buffer[j * slot.bitmap.width + i]
+                    buffer[dj,di,c] |= bb
+        pi += slot.advance.x / 64
+        pj += slot.advance.y / 64