[HarfBuzz] Building harfbuzz-ng using Android NDK
Shiva Kumar H R
shivahr at gmail.com
Mon Jun 4 23:10:31 PDT 2012
The Android widget that I had created sometime ago, that allows Indic text
to be rendered on an Android phone at an application level (without having
to root the phone), by making use of HarfBuzz-ng and FreeType libraries, is
open-sourced on http://code.google.com/p/indic-text-renderer/ .
--
Thanks & Regards,
Shiva Kumar H R
On Wed, Sep 21, 2011 at 10:29 PM, Shiva Kumar H R <shivahr at gmail.com> wrote:
> Hi,
> I am glad to inform that I could use HarfBuzz-ng and FreeType to render
> Indic text on Android Canvas.
>
> Thank you for creating such an elegant lightweight library.
>
> I referred https://github.com/anoek/ex-sdl-cairo-freetype-harfbuzz to
> come up with my sample program, the essence of which looks as below:
>
> ---- start of indic-text-rendering code snippet -----
>
> #include <hb-ft.h>
> ...
> void drawIndicText(unsigned short* text, int textLength, int xStart, int
> yBaseLine, int charHeight) {
> FT_Library ft_library;
> FT_Init_FreeType(&ft_library); /* initialize library */
>
> char* fontFilePath =
> "/sdcard/Android/data/org.iisc.mile.indictext.android/Lohit-Kannada.ttf";
> FT_Face ft_face;
> FT_New_Face(ft_library, fontFilePath, 0, &ft_face); /* create face
> object */
>
> hb_font_t *font = hb_ft_font_create(ft_face, NULL);
>
> FT_Set_Pixel_Sizes(ft_face, 0, charHeight); /* set character size */
>
> /* Create a buffer for harfbuzz to use */
> hb_buffer_t *buffer = hb_buffer_create();
>
> //hb_buffer_set_direction(buffer, HB_DIRECTION_LTR); /* or LTR */
> hb_buffer_set_script(buffer, HB_SCRIPT_KANNADA); /* see hb-unicode.h */
> //hb_buffer_set_language(buffer, hb_language_from_string("ka"));
>
> /* Layout the text */
> hb_buffer_add_utf16(buffer, text, textLength, 0, textLength);
> hb_ot_shape(font, buffer, NULL, 0, 0);
>
> int glyph_count = hb_buffer_get_length(buffer);
> hb_glyph_info_t *glyph_info = hb_buffer_get_glyph_infos(buffer, 0);
> hb_glyph_position_t *glyph_pos = hb_buffer_get_glyph_positions(buffer,
> 0);
>
> for (int i = 0; i < glyph_count; i++) {
> FT_UInt glyph_index = glyph_info[i].codepoint;
> FT_Error error = FT_Load_Glyph(ft_face, glyph_index,
> FT_LOAD_DEFAULT);
> if (error) {
> continue; /* ignore errors */
> }
> /* convert to an anti-aliased bitmap */
> error = FT_Render_Glyph(ft_face->glyph, FT_RENDER_MODE_NORMAL);
> if (error) {
> continue;
> }
>
> /* now, draw to our target surface (convert position) */
> FT_GlyphSlot slot = ft_face->glyph;
> draw_bitmap(&slot->bitmap, xStart + slot->bitmap_left, yBaseLine -
> slot->bitmap_top);
> int glyphPosX = xStart + glyph_pos[i].x_offset;
> int glyphPosY = yBaseLine - glyph_pos[i].y_offset;
> //draw_bitmap(&slot->bitmap, glyphPosX, glyphPosY, env, thiz,
> lock);
>
> /* increment pen position */
> xStart += slot->advance.x >> 6;
> //xStart += glyph_pos[i].x_advance / 64;
> }
>
> hb_buffer_destroy(buffer);
>
> hb_font_destroy(font);
> FT_Done_Face(ft_face);
> FT_Done_FreeType(ft_library);
>
> return;
> }
> ...
> ---- end of indic-text-rendering code snippet -----
>
> Few things I noticed:
> 1) I had earlier used hb_shape() but that didn't work. It worked when I
> used hb_ot_shape(). Is this by design?
>
> 2) There are a few errors in the sequence of glyphs returned by HarfBuzz
> for certain Kannada language words. In the attached snapshot, words in
> second edit-box are not rendered properly. Where should I report these
> errors and in what format?
>
> I see a test case in
> http://cgit.freedesktop.org/harfbuzz/tree/test/test-shape-complex.c . But
> I couldn't figure out how to run this. Simply running
> test-shape-complex.exe didn't help. Are there some instructions that I can
> look at?
>
>
> --
> Thanks & Regards,
> Shiva Kumar H R
> http://people.apache.org/~shivahr/
>
> On Fri, Sep 16, 2011 at 5:05 PM, Shiva Kumar H R <shivahr at gmail.com>wrote:
>
>> I have used a simple Android.mk as below and got the HarfBuzz to build on
>> Android NDK. I got below warnings though.
>>
>> harfbuzz-ng/src/hb-object-private.hh:74:2: warning: #warning "Could not
>> find any system to define atomic_int macros, library will NOT be
>> thread-safe"
>>
>> Android.mk:
>> ------Begin of Android.mk-------
>> BASE_PATH := $(call my-dir)
>> LOCAL_PATH:= $(call my-dir)
>>
>> #############################################################
>> # build the harfbuzz library
>> #
>>
>> include $(CLEAR_VARS)
>>
>> LOCAL_ARM_MODE := arm
>>
>> LOCAL_MODULE_TAGS := optional
>>
>> LOCAL_CPP_EXTENSION := .cc
>>
>> LOCAL_SRC_FILES:= \
>> src/hb-blob.cc \
>> src/hb-buffer.cc \
>> src/hb-common.cc \
>> src/hb-fallback-shape.cc \
>> src/hb-font.cc \
>> src/hb-ot-tag.cc \
>> src/hb-shape.cc \
>> src/hb-tt-font.cc \
>> src/hb-unicode.cc \
>> src/hb-ot-layout.cc \
>> src/hb-ot-map.cc \
>> src/hb-ot-shape.cc \
>> src/hb-ot-shape-complex-arabic.cc \
>> src/hb-ot-shape-complex-indic.cc \
>> src/hb-ot-shape-complex-misc.cc \
>> src/hb-ot-shape-normalize.cc \
>> src/hb-ft.cc \
>>
>> LOCAL_C_INCLUDES += \
>> $(LOCAL_PATH)/src $(LOCAL_PATH)/../freetype/include
>>
>> LOCAL_MODULE:= libharfbuzz
>>
>> LOCAL_STATIC_LIBRARIES := ft2
>>
>> include $(BUILD_SHARED_LIBRARY)
>>
>> ------End of Android.mk-------
>>
>>
>> Yet to write a sample program and see if it is actually working.
>>
>>
>> --
>> Thanks & Regards,
>> Shiva Kumar H R
>>
>>
>> On Fri, Sep 16, 2011 at 3:26 PM, Shiva Kumar H R <shivahr at gmail.com>wrote:
>>
>>> Hi,
>>> Is it possible to build harfbuzz-ng using Android-NDK. If yes, are there
>>> any instructions that I can look at?
>>>
>>> I came across Android.mk in
>>> http://tools.impjq.net/android/external/harfbuzz/ , but this seems to
>>> be the old Harfbuzz tree and has a dependency on ICU4C.
>>>
>>> --
>>> Thanks & Regards,
>>> Shiva Kumar H R
>>> http://people.apache.org/~shivahr/
>>>
>>
>>
>
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