cut overhead in fast path for text drawing
This commit is contained in:
Matthew Flatt
parent
d57f72136d
commit
b69b97c113
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@ -1061,7 +1061,9 @@
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;; is too small, so that it would look bad), then we draw character by character.
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(if (and combine?
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(can-combine-text? (* effective-scale-y (send font get-point-size))))
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;; This is combine mode.
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;; This is combine mode. It has to be a little complicated, after all,
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;; because we may need to implement font substitution ourselves, which
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;; breaks the string into multiple layouts.
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(let loop ([s s] [w 0.0] [h 0.0] [d 0.0] [a 0.0])
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(cond
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[(not s)
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@ -1146,15 +1148,16 @@
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(zero? (pango_layout_get_unknown_glyphs_count layout)))
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;; No good glyph; look for an alternate face
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(install-alternate-face ch layout font desc attrs context))
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(let ([run (extract-only-run layout)])
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(let ([layout-info (vector layout xform run)])
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;; layout-info vector is (vector _layout _xform _run _font _glyphs)
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(let ([layout-info (vector layout xform #f #f #f)])
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(extract-only-run layout layout-info)
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(hash-set! layouts (char->integer ch) layout-info)
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layout-info))))]
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layout-info)))]
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[layout (vector-ref layout-info 0)])
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(unless (equal? xform (vector-ref layout-info 1))
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(pango_cairo_update_layout cr layout)
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(vector-set! layout-info 1 xform)
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(vector-set! layout-info 2 (extract-only-run layout)))))
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(extract-only-run layout layout-info))))
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;; At this point, we have two options for dealing with the layouts.
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;; If layouts all use the same font and a single glyph, then
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;; build a glyph string with the right offsets and draw all the
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@ -1167,47 +1170,45 @@
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(unless (and
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draw?
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cache
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(not attrs) ; fast path doesn't handle underline
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((string-length s) . > . 1)
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(let ([len (string-length s)]
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[first-v (hash-ref cache (char->integer (string-ref s 0)) #f)])
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;; Check whether the fast way applies...
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[first-v (hash-ref cache (char->integer (string-ref s 0)) #f)]
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[pgi-size (ctype-sizeof _PangoGlyphInfo)])
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;; Check whether the fast way applies. The speed of this
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;; loop directly affects the responsiveness of the DrRacket
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;; editor.
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(let ([glyph-infos (malloc len _PangoGlyphInfo 'raw)] ;; assuming atomic until `free' below
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[log-clusters (malloc len _int 'raw)]
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[first-font (let* ([run (vector-ref (hash-ref layouts (char->integer (string-ref s 0))) 2)])
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(and run
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(PangoItem-font (PangoGlyphItem-item run))))]
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[first-font (vector-ref (hash-ref layouts (char->integer (string-ref s 0))) 3)]
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[first-ascent (and first-v (fl- (vector-ref first-v 1) (vector-ref first-v 2)))])
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(and
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(let loop ([i 0][dx 0.0])
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(let loop ([i 0])
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(or (= i len)
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(let* ([ch (string-ref s i)]
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[layout-info (hash-ref layouts (char->integer ch))]
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[run (vector-ref layout-info 2)]
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[font (vector-ref layout-info 3)]
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[glyphs (vector-ref layout-info 4)]
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[v (hash-ref cache (char->integer ch) #f)])
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(and run
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(and font
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v
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(fl= first-ascent
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(fl- (vector-ref v 1) (vector-ref v 2)))
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(ptr-equal? first-font
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(PangoItem-font (PangoGlyphItem-item run)))
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;; Need the same font for all glyphs for the fast path:
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(ptr-equal? first-font font)
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;; The slow path uses a top-left corner, this fast
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;; path uses a baseline, so only use the fast path
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;; if those two are consistent:
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(fl= first-ascent (fl- (vector-ref v 1) (vector-ref v 2)))
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;; Assume that the rect of the characters will pan out,
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;; and start filling in the glyph-info array:
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(let ([dest-info (cast (ptr-add glyph-infos i _PangoGlyphInfo)
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_pointer
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_PangoGlyphInfo-pointer)])
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(memcpy dest-info
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(PangoGlyphString-glyphs (PangoGlyphItem-glyphs run))
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1
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_PangoGlyphInfo)
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(memcpy glyph-infos i glyphs 1 _PangoGlyphInfo)
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;; Every glyph is is own cluster:
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(ptr-set! log-clusters _int i i)
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;; Adjust width to be consistent with integral widths
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;; used when drawing individual characters.
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(let ([w (vector-ref v 0)])
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(set-PangoGlyphInfo-width! dest-info
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(inexact->exact
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(flfloor
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(fl* w (->fl PANGO_SCALE)))))
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(loop (add1 i) (fl+ dx w))))))))
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;; This is `set-PangoGlyphInfo-width!', but without
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;; computing a
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(ptr-set! glyph-infos _uint32 'abs (+ (* i pgi-size) 4) (vector-ref v 5))
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(loop (add1 i))))))
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;; If we get here, we can use the fast way:
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(let ([glyph-string (make-PangoGlyphString len
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glyph-infos
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@ -1225,18 +1226,18 @@
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(for/fold ([w 0.0][h 0.0][d 0.0][a 0.0])
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([ch (in-string s)])
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(let ([layout (vector-ref (hash-ref layouts (char->integer ch)) 0)])
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(when (and draw? (or (not (eq? ch #\space))
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attrs))
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(when draw?
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(cairo_move_to cr (align-x/delta (+ x w) 0) (align-y/delta y 0))
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;; Here's the draw command, which uses most of the time in this mode:
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(pango_cairo_show_layout cr layout))
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(let ([v (and cache
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(hash-ref cache (char->integer ch) #f))])
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(let ([v (and cache (hash-ref cache (char->integer ch) #f))])
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(if v
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;; Used cached size:
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(values (if blank? 0.0 (+ w (vector-ref v 0)))
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(max h (vector-ref v 1))
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(max d (vector-ref v 2))
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(max a (vector-ref v 3)))
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;; Query and record size:
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(begin
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(pango_layout_get_extents layout #f logical)
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(let ([baseline (pango_layout_get_baseline layout)]
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@ -1246,21 +1247,32 @@
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[ld (integral (/ (- orig-h baseline) (exact->inexact PANGO_SCALE)))]
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[la 0.0])
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(when cache
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(hash-set! cache (char->integer ch) (vector lw lh ld la baseline)))
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(hash-set! cache (char->integer ch) (vector lw lh ld la baseline
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;; rounded width in Pango units:
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(inexact->exact
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(floor (* lw (->fl PANGO_SCALE)))))))
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(values (if blank? 0.0 (+ w lw)) (max h lh) (max d ld) (max a la))))))))))
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(when rotate? (cairo_restore cr))))))))
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(define/private (extract-only-run layout)
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(define/private (extract-only-run layout vec)
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(let* ([iter (pango_layout_get_iter layout)]
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[run (pango_layout_iter_get_run_readonly iter)]
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[done? (or (not (pango_layout_iter_next_run iter))
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(and (not (pango_layout_iter_get_run_readonly iter))
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(not (pango_layout_iter_next_run iter))))])
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(pango_layout_iter_free iter)
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(and run
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(or (and run
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done?
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(= 1 (PangoGlyphString-num_glyphs (PangoGlyphItem-glyphs run)))
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run)))
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(begin
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(vector-set! vec 2 run)
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(vector-set! vec 3 (PangoItem-font (PangoGlyphItem-item run)))
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(vector-set! vec 4 (PangoGlyphString-glyphs (PangoGlyphItem-glyphs run)))
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#t))
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(begin
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(vector-set! vec 2 #f)
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(vector-set! vec 3 #f)
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(vector-set! vec 4 #f)))))
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(define/private (install-alternate-face ch layout font desc attrs context)
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(or
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