Fix double rotation of macro circle/line center coordinates (#233)#310
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spe-ciellt merged 1 commit intogerbv:developfrom Mar 5, 2026
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The rendering code (draw.c) applies cairo_rotate() before cairo_translate() for CIRCLE, LINE21, and LINE22 macro primitives, meaning the rotation parameter already rotates the center coordinates as part of the Cairo transformation. The image copy/transform code (gerb_image.c) was updating the rotation parameter AND calling gerbv_rotate_coord() on the center coordinates. When the exported file was re-loaded, the center was rotated twice: once by the pre-rotated coordinates, and again by cairo_rotate(). Remove the redundant gerbv_rotate_coord() calls for CIRCLE and LINE21/LINE22, matching the pattern already used by LINE20, POLYGON, MOIRE, and THERMAL — all of which correctly rely on the rotation parameter alone. Fixes gerbv#233
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gerbv_gdk_draw_prim1 was the only GDK macro primitive handler that did not apply rotation to its center coordinates. Before gerbv#310, this was masked because gerb_image.c pre-rotated the center via gerbv_rotate_coord(). Removing that pre-rotation (correctly, to fix the Cairo double-rotation bug) exposed that the GDK renderer never had its own rotation handling for circles. Apply rotate_point() to the center offset before translating, matching the pattern used by all other GDK macro primitives (prim4, prim5, prim6, prim7, prim20, prim21, prim22). Fixes gerbv#352
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Summary
gerbv_rotate_coord()calls for CIRCLE, LINE21, and LINE22 macro primitives ingerb_image.cgerbv_rotate_coord()was double-applying the rotationRoot cause
The rendering code (
draw.c) usescairo_rotate()→cairo_translate()order for these primitives, so the rotation parameter already rotates the center coordinates as part of the Cairo transformation. The image copy/transform code was additionally pre-rotating the center coordinates viagerbv_rotate_coord(), causing a double rotation when the exported file was re-loaded.LINE20, POLYGON, MOIRE, and THERMAL already handle this correctly — they only update the rotation parameter without calling
gerbv_rotate_coord(). This fix makes CIRCLE, LINE21, and LINE22 consistent.Test plan
Fixes #233