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backend_common: fix handling of large shadow images 

For big windows, their shadow images might exceed the maximum request
length limit of Xorg. libxcb will shutdown the connection to X server if
we try to send that image. So we have to break the image apart and send
it piecemeal.

In the future we probably should migrate to MIT-SHM.

Fixes #255 #274

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
This commit is contained in:
Yuxuan Shui 2020-02-07 21:27:01 +00:00
parent b026708026
commit 69b3eee76b
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GPG Key ID: 37C999F617EA1A47
1 changed files with 30 additions and 6 deletions
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36
src/backend/backend_common.c
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@ -1,7 +1,7 @@
// SPDX-License-Identifier: MPL-2.0
// Copyright (c) Yuxuan Shui <yshuiv7@gmail.com>
#include <string.h>
#include <math.h>
#include <string.h>
#include <xcb/render.h>
#include <xcb/xcb_image.h>
#include <xcb/xcb_renderutil.h>
@ -9,10 +9,10 @@
#include "backend/backend.h"
#include "backend/backend_common.h"
#include "common.h"
#include "kernel.h"
#include "config.h"
#include "utils.h"
#include "kernel.h"
#include "log.h"
#include "utils.h"
#include "win.h"
#include "x.h"
@ -227,7 +227,32 @@ bool build_shadow(xcb_connection_t *c, xcb_drawable_t d, double opacity, const i
gc = x_new_id(c);
xcb_create_gc(c, gc, shadow_pixmap, 0, NULL);
xcb_image_put(c, shadow_pixmap, gc, shadow_image, 0, 0, 0);
// We need to make room for protocol metadata in the request. The metadata should
// be 24 bytes plus padding, let's be generous and give it 1kb
auto maximum_image_size = xcb_get_maximum_request_length(c) * 4 - 1024;
auto maximum_row =
to_u16_checked(clamp(maximum_image_size / shadow_image->stride, 0, UINT16_MAX));
if (maximum_row <= 0) {
log_error("X server request size limit is too restrictive, or the shadow "
"image is too wide for us to send a single row of the shadow "
"image. Shadow size: %dx%d",
width, height);
goto shadow_picture_err;
}
for (uint32_t row = 0; row < shadow_image->height; row += maximum_row) {
auto batch_height = maximum_row;
if (batch_height > shadow_image->height - row) {
batch_height = to_u16_checked(shadow_image->height - row);
}
uint32_t offset = row * shadow_image->stride / sizeof(*shadow_image->data);
xcb_put_image(c, shadow_image->format, shadow_pixmap, gc,
shadow_image->width, batch_height, 0, to_i16_checked(row),
0, shadow_image->depth, shadow_image->stride * batch_height,
shadow_image->data + offset);
}
xcb_render_composite(c, XCB_RENDER_PICT_OP_SRC, shadow_pixel, shadow_picture,
shadow_picture_argb, 0, 0, 0, 0, 0, 0, shadow_image->width,
shadow_image->height);
@ -283,8 +308,7 @@ default_backend_render_shadow(backend_t *backend_data, int width, int height,
return ret;
}
static struct conv **
generate_box_blur_kernel(struct box_blur_args *args, int *kernel_count) {
static struct conv **generate_box_blur_kernel(struct box_blur_args *args, int *kernel_count) {
int r = args->size * 2 + 1;
assert(r > 0);
auto ret = ccalloc(2, struct conv *);