Commita5e9960dRecorded11 Dec 2025Repositorysigil-studio

Add draw-text-centered and transform demo

Changed
 src/sigil/studio/font.sgl |   9 ++++++---
 test/test-transforms.sgl  | 144 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 150 insertions(+), 3 deletions(-)
Diff
src/sigil/studio/font.sglmodified
@@ -12,8 +12,11 @@
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font? font-size font-line-height
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;; Text rendering
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draw-text draw-text-char text-width)
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draw-text draw-text-char text-width
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draw-text-centered)
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(begin
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;; Native functions are automatically available after native module init.
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))
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;; Draw text centered on position x, y
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(define (draw-text-centered font text x y)
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(let ((w (text-width font text)))
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(draw-text font text (- x (/ w 2)) y)))))
test/test-transforms.sgladded
@@ -0,0 +1,144 @@
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;;; test-transforms.sgl - Demo of transform stack
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(import (sigil core)
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(sigil studio app)
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(sigil studio graphics)
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(sigil studio font))
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(define (label text x y)
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(set-color 0.7 0.7 0.7)
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(draw-text-centered *font* text x y))
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(define *font* #f)
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(define *angle* 0.0)
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(define *time* 0.0)
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(define (on-init)
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(set! *font* (load-font "test/Saucer.ttf" 18)))
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(define (on-frame)
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(begin-frame)
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(clear-screen 0.05 0.05 0.1)
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;; Update time
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(set! *time* (+ *time* 0.016))
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(set! *angle* (+ *angle* 0.02))
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;; Title
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(when *font*
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(set-color 0.0 1.0 1.0)
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(draw-text-centered *font* "Transform Stack Demo" 400 30))
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;; 1. Simple rotation around center
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(push-transform)
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(translate 150 150)
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(rotate *angle*)
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(set-color 1.0 0.3 0.3)
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(draw-filled-rect -40 -40 80 80)
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(set-color 1.0 1.0 1.0)
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(draw-rect -40 -40 80 80)
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(pop-transform)
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(when *font*
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(label "Rotating" 150 250))
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;; 2. Scaling pulse
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(push-transform)
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(translate 400 150)
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(define pulse (+ 0.7 (* 0.3 (sin (* *time* 3)))))
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(scale pulse pulse)
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(set-color 0.3 1.0 0.3)
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(draw-filled-rect -40 -40 80 80)
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(set-color 1.0 1.0 1.0)
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(draw-rect -40 -40 80 80)
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(pop-transform)
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(when *font*
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(label "Pulsing" 400 250))
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;; 3. Rotation + scale combined
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(push-transform)
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(translate 650 150)
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(rotate (* *angle* -0.5))
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(scale (+ 0.8 (* 0.2 (cos (* *time* 2))))
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(+ 0.8 (* 0.2 (sin (* *time* 2)))))
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(set-color 0.3 0.3 1.0)
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(draw-filled-rect -40 -40 80 80)
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(set-color 1.0 1.0 1.0)
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(draw-rect -40 -40 80 80)
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(pop-transform)
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(when *font*
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(label "Combined" 650 250))
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;; 4. Nested transforms - orbiting squares
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(push-transform)
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(translate 150 400)
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;; Outer rotation
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(push-transform)
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(rotate *angle*)
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;; Draw center
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(set-color 1.0 1.0 0.0)
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(draw-filled-rect -15 -15 30 30)
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;; Orbiting square 1
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(push-transform)
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(translate 70 0)
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(rotate (* *angle* -2))
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(set-color 1.0 0.5 0.0)
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(draw-filled-rect -12 -12 24 24)
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(pop-transform)
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;; Orbiting square 2
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(push-transform)
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(translate -70 0)
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(rotate (* *angle* -2))
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(set-color 0.0 1.0 0.5)
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(draw-filled-rect -12 -12 24 24)
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(pop-transform)
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(pop-transform)
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(pop-transform)
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(when *font*
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(label "Orbiting" 150 500))
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;; 5. Triangle rotation
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(push-transform)
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(translate 400 400)
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(rotate (* *angle* 0.7))
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(set-color 1.0 0.0 1.0)
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(fill-triangle 0 -50 -43 25 43 25)
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(set-color 1.0 1.0 1.0)
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(draw-triangle 0 -50 -43 25 43 25)
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(pop-transform)
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(when *font*
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(label "Triangle" 400 500))
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;; 6. Line spinner
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(push-transform)
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(translate 650 400)
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(let loop ((i 0))
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(when (< i 8)
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(push-transform)
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(rotate (+ *angle* (* i 0.785))) ; i * pi/4
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(set-color (/ i 8.0) 1.0 (- 1.0 (/ i 8.0)))
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(draw-line 0 0 60 0)
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(pop-transform)
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(loop (+ i 1))))
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(pop-transform)
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(when *font*
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(label "Spinner" 650 500))
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(when (key-pressed? 'escape)
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(request-quit))
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(end-frame))
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(define (on-cleanup) #t)
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(app-run on-init on-frame on-cleanup "Transform Demo" 800 550)