Rofi dynamic theme/image preview + Rofi-Blocks = blurry images

[vredesbyyrd]

Hello. Initial, limited testing points to an issue in rofi-blocks, so I made a bug report on the rofi-blocks repo. Although I've been wrong many of times so i'm starting a conversation here with hopes someone more knowledgeable than me will have some ideas. The image preview is such a great feature and I'd love to take advantage of it.

Since the rofi 1.7.5 release there is a new "dynamic" theme mode. It allows you to split the list view and show an image preview on one half. See documentation here. This feature is perfect for the rofi-blocks-jellyfin client I am working on. Unfortunately there seems to be a bug present when using rofi-blocks that's not present in rofi.

BUG: When rofi-blocks first loads and when rendering a "new page", ie page up/down, the initially focused image is rendered correctly, but when cycling through lines individually the preview image is blurry until a new page is rendered. I'm using rofi wayland, but the bug is present when using the -x11 flag so I do not think it's wayland specific.

Here is a gist for the fullscreen-preview.rasi and two very basic debugging scripts. One for rofi-blocks and one for rofi-script mode. You just need to modify the IMAGE_DIRECTORY. debug scripts

• rofi-wayland 1.7.9.1-1
• rofi-blocks-meson-git r170.d75a9da-1
• archlinux + niri

If anyone has thoughts on what could be causing the images to not render correctly I would love to hear them. Thanks for your time!

Rof-Blocks video:

rofi_blocks_image_debug.mp4

Rofi-script video:

rofi_script_mode_image_debug.mp4

[DaveDavenport]

Rofi calls this function to get the preview icon:
https://github.com/OmarCastro/rofi-blocks/blob/d75a9da1516daeef33a13714dfe19d2da9d6c819/src/blocks.c#L449

It looks like it fetches it once, but does not re-fetches it if its called with another size.

So if the preview image loads first, you get the high-res image first (both in the small and big preview).. if the smaller image loads first, you also get this smaller one in the high-res image.

This will need a small fix in rofi-blocks.

[DaveDavenport]

Something like this: https://github.com/davatorium/rofi/blob/next/source/modes/script.c#L527

[vredesbyyrd]

That would explain it. I much appreciate the rundown. I do not know c and I would not call myself a programmer. That said, I did the abominable thing asked claude to help.

In script.c, script_get_icon there is const guint scale = display_scale();. I think display_scale() requires display.h, which is not available to plugins? I could be reading this very wrong. I was able to "fix" the icon issue with:

static guint blocks_get_display_scale(void) {
    // Try to get scale from GDK if available
    const char *scale_env = g_getenv("GDK_SCALE");
    if (scale_env) {
        double scale_val = g_strtod(scale_env, NULL);
        if (scale_val > 0) {
            return (guint)(scale_val + 0.5); // Round to nearest integer
        }
    }

    // Fallback: check for HiDPI indicators
    const char *dpi_env = g_getenv("GDK_DPI_SCALE");
    if (dpi_env) {
        double dpi_scale = g_strtod(dpi_env, NULL);
        if (dpi_scale > 1.5) {
            return 2;
        }
    }
    return 1;
}

static cairo_surface_t * blocks_mode_get_icon ( const Mode *sw, unsigned int selected_line, unsigned int height ){
    PageData * pageData = mode_get_private_data_current_page( sw );
    LineData * lineData = page_data_get_line_by_index_or_else(pageData, selected_line, NULL);
    if(lineData == NULL){
        return NULL;
    }

    const gchar * icon = lineData->icon;
    if(icon == NULL || icon[0] == '\0'){
        return NULL;
    }

    // Get the current display scale
    const guint scale = blocks_get_display_scale();

    if(lineData->icon_fetch_uid > 0 &&
       lineData->icon_fetch_size == height &&
       lineData->icon_fetch_scale == scale) {
        return rofi_icon_fetcher_get(lineData->icon_fetch_uid);
    }

    lineData->icon_fetch_uid = rofi_icon_fetcher_query(icon, height);
    lineData->icon_fetch_size = height;
    lineData->icon_fetch_scale = scale;

    return rofi_icon_fetcher_get(lineData->icon_fetch_uid);
}

And adding icon_fetch_size and icon_fetch_scale to page_data.h. Do you mind telling me if I did anything stupid here?

[DaveDavenport]

That scale is wrong, we don't get that from ENV variables, this is information propagated via wayland.
This can only really be fixed 'right' for the next rofi release where wayland is merged back into mainline.

But I think fixing rofi-blocks more belongs at their github then here.

[vredesbyyrd]

That scale is wrong, we don't get that from ENV variables, this is information propagated via wayland.
This can only really be fixed 'right' for the next rofi release where wayland is merged back into mainline.

Yeah, further I dug into rofi source i realized getting scale via ENV variables is likely way off base.

But I think fixing rofi-blocks more belongs at their github then here.

Heard. I'll link to this discussion at the rofi-blocks repo so the maintainer can see it, need be. For the time being I have a hackish workaround for personal use.

Thanks again,