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start adding colour text rendering 

try eg.

	vips text x.png 😀 --rgba --dpi 300

But it's not working :( need to tyweak something else?
This commit is contained in:
John Cupitt 2021-04-12 10:59:50 +01:00
parent db22eb4d4f
commit 8412b8233c
1 changed files with 45 additions and 12 deletions
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57
libvips/create/text.c
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@ -94,6 +94,7 @@ typedef struct _VipsText {
gboolean justify;
int dpi;
char *fontfile;
gboolean rgba;
FT_Bitmap bitmap;
PangoContext *context;
@ -342,6 +343,9 @@ vips_text_build( VipsObject *object )
VipsText *text = (VipsText *) object;
VipsRect extents;
int bands;
VipsInterpretation interpretation;
FT_Pixel_Mode pixel_mode;
int y;
if( VIPS_OBJECT_CLASS( vips_text_parent_class )->build( object ) )
@ -399,8 +403,19 @@ vips_text_build( VipsObject *object )
return( -1 );
}
if( text->rgba ) {
interpretation = VIPS_INTERPRETATION_sRGB;
bands = 4;
pixel_mode = FT_PIXEL_MODE_BGRA;
}
else {
interpretation = VIPS_INTERPRETATION_MULTIBAND;
bands = 1;
pixel_mode = FT_PIXEL_MODE_GRAY;
}
text->bitmap.width = extents.width;
text->bitmap.pitch = (text->bitmap.width + 3) & ~3;
text->bitmap.pitch = (bands * text->bitmap.width + 3) & ~3;
text->bitmap.rows = extents.height;
if( !(text->bitmap.buffer =
VIPS_ARRAY( NULL,
@ -409,25 +424,31 @@ vips_text_build( VipsObject *object )
return( -1 );
}
text->bitmap.num_grays = 256;
text->bitmap.pixel_mode = ft_pixel_mode_grays;
text->bitmap.pixel_mode = pixel_mode;
memset( text->bitmap.buffer, 0x00,
text->bitmap.pitch * text->bitmap.rows );
pango_ft2_render_layout( &text->bitmap, text->layout,
-extents.left, -extents.top );
/* Set DPI as pixels/mm.
*/
vips_image_init_fields( create->out,
text->bitmap.width, text->bitmap.rows, bands,
VIPS_FORMAT_UCHAR, VIPS_CODING_NONE,
interpretation, text->dpi / 25.4, text->dpi / 25.4 );
g_mutex_unlock( vips_text_lock );
vips_image_init_fields( create->out,
text->bitmap.width, text->bitmap.rows, 1,
VIPS_FORMAT_UCHAR, VIPS_CODING_NONE,
VIPS_INTERPRETATION_MULTIBAND,
1.0, 1.0 );
vips_image_pipelinev( create->out,
VIPS_DEMAND_STYLE_ANY, NULL );
vips_image_pipelinev( create->out, VIPS_DEMAND_STYLE_ANY, NULL );
create->out->Xoffset = extents.left;
create->out->Yoffset = extents.top;
if( text->rgba ) {
/* Convert premultiplied BGRA to RGBA.
*/
}
for( y = 0; y < text->bitmap.rows; y++ )
if( vips_image_write_line( create->out, y,
(VipsPel *) text->bitmap.buffer +
@ -534,6 +555,13 @@ vips_text_class_init( VipsTextClass *class )
G_STRUCT_OFFSET( VipsText, fontfile ),
NULL );
VIPS_ARG_BOOL( class, "rgba", 9,
_( "RGBA" ),
_( "Enable RGBA output" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsText, rgba ),
FALSE );
}
static void
@ -563,17 +591,22 @@ vips_text_init( VipsText *text )
* * @justify: %gboolean, justify lines
* * @dpi: %gint, render at this resolution
* * @autofit_dpi: %gint, read out auto-fitted DPI
* * @rgba: %gboolean, enable RGBA output
* * @spacing: %gint, space lines by this in points
*
* Draw the string @text to an image. @out is a one-band 8-bit
* Draw the string @text to an image. @out is normally a one-band 8-bit
* unsigned char image, with 0 for no text and 255 for text. Values between
* are used for anti-aliasing.
*
* Set @rgba to enable RGBA output. This is useful for colour emoji rendering,
* or support for pango markup features like `<span
* foreground="red">Red!</span>`.
*
* @text is the text to render as a UTF-8 string. It can contain Pango markup,
* for example "&lt;i&gt;The&lt;/i&gt;Guardian".
* for example `<i>The</i>Guardian`.
*
* @font is the font to render with, as a fontconfig name. Examples might be
* "sans 12" or perhaps "bitstream charter bold 10".
* `sans 12` or perhaps `bitstream charter bold 10`.
*
* You can specify a font to load with @fontfile. You'll need to also set the
* name of the font with @font.