From 1da726047a455a79b81cff64d7c2c0174aee7763 Mon Sep 17 00:00:00 2001
From: Yuxuan Shui <yshuiv7@gmail.com>
Date: Sun, 9 Jun 2019 01:01:53 +0100
Subject: [PATCH] new backend: don't assume center of blur kernel is 1

Also fill the center of parsed kernel with 1. This shouldn't change the
behavior of the old backends since they will modify the center of the
kernels.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
---
 src/backend/gl/gl_common.c    |  7 ++-----
 src/backend/xrender/xrender.c | 12 ++++++++----
 src/config.c                  |  2 +-
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/backend/gl/gl_common.c b/src/backend/gl/gl_common.c
index 10092a9..02913e1 100644
--- a/src/backend/gl/gl_common.c
+++ b/src/backend/gl/gl_common.c
@@ -18,6 +18,7 @@
 #include "utils.h"
 
 #include "backend/gl/gl_common.h"
+#include "backend/backend_common.h"
 
 #define GLSL(version, ...) "#version " #version "\n" #__VA_ARGS__
 #define QUOTE(...) #__VA_ARGS__
@@ -713,11 +714,7 @@ static bool gl_init_blur(struct gl_data *gd, conv *const *const kernels, int nke
 		for (int j = 0; j < height; ++j) {
 			for (int k = 0; k < width; ++k) {
 				double val;
-				if (height / 2 == j && width / 2 == k) {
-					val = 1;
-				} else {
-					val = kern->data[j * width + k];
-				}
+				val = kern->data[j * width + k];
 				if (val == 0) {
 					continue;
 				}
diff --git a/src/backend/xrender/xrender.c b/src/backend/xrender/xrender.c
index defe0d3..57fcd9a 100644
--- a/src/backend/xrender/xrender.c
+++ b/src/backend/xrender/xrender.c
@@ -183,9 +183,10 @@ static bool blur(backend_t *backend_data, double opacity, const region_t *reg_bl
 		// be applied on source picture, to get the nearby pixels outside the
 		// window.
 		// TODO cache converted blur_kerns
-		xcb_render_set_picture_filter(
-		    c, src_pict, to_u16_checked(strlen(filter)), filter,
-		    to_u32_checked(xd->x_blur_kernel[i]->size), xd->x_blur_kernel[i]->kernel);
+		xcb_render_set_picture_filter(c, src_pict, to_u16_checked(strlen(filter)),
+		                              filter,
+		                              to_u32_checked(xd->x_blur_kernel[i]->size),
+		                              xd->x_blur_kernel[i]->kernel);
 
 		if (i < xd->x_blur_kernel_count - 1 || i == 0) {
 			// This is not the last pass, or this is the first pass
@@ -552,7 +553,10 @@ backend_t *backend_xrender_init(session_t *ps) {
 
 	xd->x_blur_kernel = ccalloc(ps->o.blur_kernel_count, struct x_convolution_kernel *);
 	for (int i = 0; i < ps->o.blur_kernel_count; i++) {
-		x_create_convolution_kernel(ps->o.blur_kerns[i], 1, &xd->x_blur_kernel[i]);
+		int center = ps->o.blur_kerns[i]->h * ps->o.blur_kerns[i]->w / 2;
+		x_create_convolution_kernel(ps->o.blur_kerns[i],
+		                            ps->o.blur_kerns[i]->data[center],
+		                            &xd->x_blur_kernel[i]);
 	}
 	xd->x_blur_kernel_count = ps->o.blur_kernel_count;
 	return &xd->base;
diff --git a/src/config.c b/src/config.c
index 1f46df9..536c1b3 100644
--- a/src/config.c
+++ b/src/config.c
@@ -139,7 +139,7 @@ conv *parse_blur_kern(const char *src, const char **endptr, bool *hasneg) {
 	for (int i = 0; i < width * height; ++i) {
 		// Ignore the center element
 		if (i == skip) {
-			matrix->data[i] = 0;
+			matrix->data[i] = 1;
 			continue;
 		}
 		if (src == (pc = parse_readnum(src, &val))) {