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improve scaling of SVG images
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We were not scaling images with fixed absolute dimensions.
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@jcupitt
jcupitt committed Jun 6, 2022
1 parent 586fb31 commit 2d0c6b3
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Showing 3 changed files with 57 additions and 71 deletions.
68 changes: 28 additions & 40 deletions libvips/foreign/svgload.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -377,8 +377,8 @@ svg_css_length_to_pixels( RsvgLength length, double dpi )
value = dpi * value / 6;
break;
default:
/* Probably RSVG_UNIT_PERCENT. We can't know what the pixel
* value is without more information.
/* Probably RSVG_UNIT_PERCENT. We can't know what the
* pixel value is without more information.
*/
value = 0;
}
Expand All @@ -397,6 +397,7 @@ vips_foreign_load_svg_get_natural_size( VipsForeignLoadSvg *svg,
double height;

#if LIBRSVG_CHECK_VERSION( 2, 52, 0 )

if( !rsvg_handle_get_intrinsic_size_in_pixels( svg->page,
&width, &height ) ) {
RsvgRectangle zero_rect, viewbox;
Expand All @@ -412,19 +413,20 @@ vips_foreign_load_svg_get_natural_size( VipsForeignLoadSvg *svg,
&has_height, &iheight,
&has_viewbox, &viewbox );

/* After librsvg 2.54.0, the `has_width` and `has_height` arguments
* always returns `TRUE`, since with SVG2 all documents *have* a
* default width and height of `100%`.
*/
#if LIBRSVG_CHECK_VERSION( 2, 54, 0 )
/* After librsvg 2.54.0, the `has_width` and `has_height`
* arguments always returns `TRUE`, since with SVG2 all
* documents *have* a default width and height of `100%`.
*/
width = svg_css_length_to_pixels( iwidth, svg->dpi );
height = svg_css_length_to_pixels( iheight, svg->dpi );

has_width = width > 0.0;
has_height = height > 0.0;

if( has_width && has_height ) {
/* Success! Taking the viewbox into account is not needed.
/* Success! Taking the viewbox into account is not
* needed.
*/
}
else if( has_width && has_viewbox ) {
Expand Down Expand Up @@ -460,23 +462,26 @@ vips_foreign_load_svg_get_natural_size( VipsForeignLoadSvg *svg,

if( width <= 0.0 ||
height <= 0.0 ) {
/* We haven't found a usable set of sizes, so try working out
* the visible area.
/* We haven't found a usable set of sizes, so try
* working out the visible area.
*/
rsvg_handle_get_geometry_for_layer( svg->page, NULL,
&zero_rect, &viewbox, NULL, NULL );
width = viewbox.x + viewbox.width;
height = viewbox.y + viewbox.height;
}
}

#else /*!LIBRSVG_CHECK_VERSION( 2, 52, 0 )*/

{
RsvgDimensionData dimensions;

rsvg_handle_get_dimensions( svg->page, &dimensions );
width = dimensions.width;
height = dimensions.height;
}

#endif /*LIBRSVG_CHECK_VERSION( 2, 52, 0 )*/

/* width or height below 0.5 can't be rounded to 1.
Expand All @@ -499,44 +504,19 @@ vips_foreign_load_svg_get_scaled_size( VipsForeignLoadSvg *svg,
{
double width;
double height;
double scale;

/* Get dimensions with the default dpi.
*/
rsvg_handle_set_dpi( svg->page, 72.0 );
if( vips_foreign_load_svg_get_natural_size( svg, &width, &height ) )
return( -1 );

/* Calculate dimensions at required dpi/scale.
/* We scale up with cairo --- scaling with rsvg_handle_set_dpi() will
* fail for SVGs with absolute sizes.
*/
scale = svg->scale * svg->dpi / 72.0;
if( scale != 1.0 ) {
double scaled_width;
double scaled_height;

rsvg_handle_set_dpi( svg->page, scale * 72.0 );
if( vips_foreign_load_svg_get_natural_size( svg,
&scaled_width, &scaled_height ) )
return( -1 );

if( scaled_width == width &&
scaled_height == height ) {
/* SVG without width and height always reports the same
* dimensions regardless of dpi. Apply dpi/scale using
* cairo instead.
*/
svg->cairo_scale = scale;
width *= scale;
height *= scale;
}
else {
/* SVG with width and height reports correctly scaled
* dimensions.
*/
width = scaled_width;
height = scaled_height;
}
}
svg->cairo_scale = svg->scale * svg->dpi / 72.0;
width *= svg->cairo_scale;
height *= svg->cairo_scale;

*out_width = VIPS_ROUND_UINT( width );
*out_height = VIPS_ROUND_UINT( height );
Expand All @@ -563,7 +543,8 @@ vips_foreign_load_svg_parse( VipsForeignLoadSvg *svg, VipsImage *out )
4, VIPS_FORMAT_UCHAR,
VIPS_CODING_NONE, VIPS_INTERPRETATION_sRGB, res, res );

/* We render to a linecache, so fat strips work well.
/* We render to a cache with a couple of rows of tiles, so fat strips
* work well.
*/
if( vips_image_pipelinev( out, VIPS_DEMAND_STYLE_FATSTRIP, NULL ) )
return( -1 );
Expand Down Expand Up @@ -613,10 +594,14 @@ vips_foreign_load_svg_generate( VipsRegion *or,
* running inside a non-threaded tilecache.
*/
#if LIBRSVG_CHECK_VERSION( 2, 46, 0 )

{
RsvgRectangle viewport;
GError *error = NULL;

/* No need to scale -- we always set the viewport to the
* whole image, and set the region to draw on the surface.
*/
cairo_translate( cr, -r->left, -r->top );
viewport.x = 0;
viewport.y = 0;
Expand All @@ -634,7 +619,9 @@ vips_foreign_load_svg_generate( VipsRegion *or,

cairo_destroy( cr );
}

#else /*!LIBRSVG_CHECK_VERSION( 2, 46, 0 )*/

cairo_scale( cr, svg->cairo_scale, svg->cairo_scale );
cairo_translate( cr, -r->left / svg->cairo_scale,
-r->top / svg->cairo_scale );
Expand All @@ -648,6 +635,7 @@ vips_foreign_load_svg_generate( VipsRegion *or,
}

cairo_destroy( cr );

#endif /*LIBRSVG_CHECK_VERSION( 2, 46, 0 )*/

/* Cairo makes pre-multipled BRGA -- we must byteswap and unpremultiply.
Expand Down
30 changes: 14 additions & 16 deletions libvips/iofuncs/ginputsource.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -99,21 +99,21 @@ vips_g_input_stream_finalize( GObject *object )
{
VipsGInputStream *gstream = VIPS_G_INPUT_STREAM( object );

VIPS_FREEF( g_object_unref, gstream->source );
VIPS_UNREF( gstream->source );

G_OBJECT_CLASS( vips_g_input_stream_parent_class )->finalize( object );
}

static goffset
vips_g_input_stream_tell( GSeekable *seekable )
{
VipsSource *source = VIPS_G_INPUT_STREAM( seekable )->source;
VipsGInputStream *gstream = VIPS_G_INPUT_STREAM( seekable );

goffset pos;

VIPS_DEBUG_MSG( "vips_g_input_stream_tell:\n" );

pos = vips_source_seek( source, 0, SEEK_CUR );
pos = vips_source_seek( gstream->source, 0, SEEK_CUR );
if( pos == -1 )
return( 0 );

Expand All @@ -123,12 +123,12 @@ vips_g_input_stream_tell( GSeekable *seekable )
static gboolean
vips_g_input_stream_can_seek( GSeekable *seekable )
{
VipsSource *source = VIPS_G_INPUT_STREAM( seekable )->source;
VipsGInputStream *gstream = VIPS_G_INPUT_STREAM( seekable );

VIPS_DEBUG_MSG( "vips_g_input_stream_can_seek: %d\n",
!source->is_pipe );
!gstream->source->is_pipe );

return( !source->is_pipe );
return( !gstream->source->is_pipe );
}

static int
Expand All @@ -149,12 +149,12 @@ static gboolean
vips_g_input_stream_seek( GSeekable *seekable, goffset offset,
GSeekType type, GCancellable *cancellable, GError **error )
{
VipsSource *source = VIPS_G_INPUT_STREAM( seekable )->source;
VipsGInputStream *gstream = VIPS_G_INPUT_STREAM( seekable );

VIPS_DEBUG_MSG( "vips_g_input_stream_seek: offset = %" G_GINT64_FORMAT
", type = %d\n", offset, type );

if( vips_source_seek( source, offset,
if( vips_source_seek( gstream->source, offset,
seek_type_to_lseek( type ) ) == -1 ) {
g_set_error( error, G_IO_ERROR,
G_IO_ERROR_FAILED,
Expand Down Expand Up @@ -189,17 +189,16 @@ static gssize
vips_g_input_stream_read( GInputStream *stream, void *buffer, gsize count,
GCancellable *cancellable, GError **error )
{
VipsSource *source;
gssize res;
VipsGInputStream *gstream = VIPS_G_INPUT_STREAM( stream );

source = VIPS_G_INPUT_STREAM( stream )->source;
gssize res;

VIPS_DEBUG_MSG( "vips_g_input_stream_read: count: %zd\n", count );

if( g_cancellable_set_error_if_cancelled( cancellable, error ) )
return( -1 );

if( (res = vips_source_read( source, buffer, count )) == -1 )
if( (res = vips_source_read( gstream->source, buffer, count )) == -1 )
g_set_error( error, G_IO_ERROR,
G_IO_ERROR_FAILED,
_( "Error while reading: %s" ),
Expand All @@ -212,17 +211,16 @@ static gssize
vips_g_input_stream_skip( GInputStream *stream, gsize count,
GCancellable *cancellable, GError **error )
{
VipsSource *source;
gssize position;
VipsGInputStream *gstream = VIPS_G_INPUT_STREAM( stream );

source = VIPS_G_INPUT_STREAM( stream )->source;
gssize position;

VIPS_DEBUG_MSG( "vips_g_input_stream_skip: count: %zd\n", count );

if( g_cancellable_set_error_if_cancelled( cancellable, error ) )
return( -1 );

position = vips_source_seek( source, count, SEEK_CUR );
position = vips_source_seek( gstream->source, count, SEEK_CUR );
if( position == -1 ) {
g_set_error( error, G_IO_ERROR,
G_IO_ERROR_FAILED,
Expand Down
30 changes: 15 additions & 15 deletions libvips/iofuncs/init.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -742,21 +742,6 @@ vips_shutdown( void )

vips_cache_drop_all();

/* In dev releases, always show leaks. But not more than once, it's
* annoying.
*/
#ifndef DEBUG_LEAK
if( vips__leak )
#endif /*DEBUG_LEAK*/
{
static gboolean done = FALSE;

if( !done ) {
done = TRUE;
vips_leak();
}
}

#if ENABLE_DEPRECATED
im_close_plugins();
#endif
Expand Down Expand Up @@ -787,6 +772,21 @@ vips_shutdown( void )
VIPS_FREE( vips__argv0 );
VIPS_FREE( vips__prgname );
VIPS_FREEF( g_timer_destroy, vips__global_timer );

/* In dev releases, always show leaks. But not more than once, it's
* annoying.
*/
#ifndef DEBUG_LEAK
if( vips__leak )
#endif /*DEBUG_LEAK*/
{
static gboolean done = FALSE;

if( !done ) {
done = TRUE;
vips_leak();
}
}
}

static gboolean
Expand Down

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