Attachment 139844 Details for Bug 105027 – assembling: Fix assembling of frames for non-reverse stripes

[patch] assembling: Fix assembling of frames for non-reverse stripes

assembling-Fix-assembling-of-frames-for-non-revers.patch (text/plain), 1.51 KB, created by Bastien Nocera on 2018-05-30 09:17:36 UTC

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Creator: Bastien Nocera

Created: 2018-05-30 09:17:36 UTC

Size: 1.51 KB

patch

obsolete

>From 37bb59df131503b2853427053b20b5c90349e1ed Mon Sep 17 00:00:00 2001
>From: Timur Celik <mail@timurcelik.de>
>Date: Sat, 10 Feb 2018 00:37:33 +0100
>Subject: [PATCH] assembling: Fix assembling of frames for non-reverse stripes
>
>Every frame stores the delta from the previous frame, in reverse mode
>it stores the delta to the next frame. This causes images to use the
>wrong delta while assembling in forward mode.
>
>The broken assembling in forward mode will create a small error for
>linear motion, because the delta of all frames is approximately the
>same in this case. But if you move your finger, stop and then continue
>moving in a single scan, the misplaced frames should be visible in
>the assembled output.
>
>This could result in false positives and verification failing.
>
>https://bugs.freedesktop.org/show_bug.cgi?id=105027
>---
> libfprint/assembling.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
>diff --git a/libfprint/assembling.c b/libfprint/assembling.c
>index 2c4ccc6..ec37a25 100644
>--- a/libfprint/assembling.c
>+++ b/libfprint/assembling.c
>@@ -280,11 +280,18 @@ struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
> 	do {
> 		fpi_frame = stripe->data;
> 
>-		y += fpi_frame->delta_y;
>-		x += fpi_frame->delta_x;
>+		if(reverse) {
>+			y += fpi_frame->delta_y;
>+			x += fpi_frame->delta_x;
>+		}
> 
> 		aes_blit_stripe(ctx, img, fpi_frame, x, y);
> 
>+		if(!reverse) {
>+			y += fpi_frame->delta_y;
>+			x += fpi_frame->delta_x;
>+		}
>+
> 		stripe = g_slist_next(stripe);
> 		i++;
> 	} while (i < stripes_len);
>-- 
>2.17.0

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Attachments on bug 105027: 137252 | 139758 | 139759 | 139844 | 139845

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