Plugin for saving the cover image to file #6813

zwim · 2020-10-22T09:53:43Z

If the plugin is enabled the following actions can be selected:

On opening of a document, the cover is saved to a file (format png).
If the filename exists, a backup of the original is created.
On closing of the document this file can be deleted and the original file can be restored.
Certain documents can be excluded from image generation.

This plugin can be used to change the sleep-screen on Tolinos (filename: /sdcard/suspend_others.jpg) as long KOReader has an opened document. On close of KOReader the original sleep screen is restored.

This change is

poire-z

I'm fine with the principle (and quite a few people were requested that :)
Dunno if we should disable this plugin on some platforms like Kobo or Kindle where it would not make any sense as there are no other tool that could use such generated image?

(I think I'd also wouldn't mind if this was not a plugin but part of the core Screensaver code and menu.)

plugins/coverimage.koplugin/main.lua

poire-z · 2020-10-22T10:54:22Z

plugins/coverimage.koplugin/main.lua

+    end
+end
+
+function CoverImage:onDocSettingsLoad(doc_settings, document)


Not sure it's the best event/timing (document is not yet fully opened I think), best to catch the ReaderReady event with onReaderReady):

koreader/frontend/apps/reader/readerui.lua

Lines 405 to 424 in dda9052

-- Allow others to change settings based on external factors

-- Must be called after plugins are loaded & before setting are read.

self:handleEvent(Event:new("DocSettingsLoad", self.doc_settings, self.document))

-- we only read settings after all the widgets are initialized

self:handleEvent(Event:new("ReadSettings", self.doc_settings))

for _,v in ipairs(self.postInitCallback) do

v()

end

self.postInitCallback = nil

-- Now that document is loaded, store book metadata in settings

-- (so that filemanager can use it from sideCar file to display

-- Book information).

self.doc_settings:saveSetting("doc_props", self.document:getProps())

-- After initialisation notify that document is loaded and rendered

-- CREngine only reports correct page count after rendering is done

-- Need the same event for PDF document

self:handleEvent(Event:new("ReaderReady", self.doc_settings))

document is not passed and you need it, so either add it being passed above, but it's also immediately available to all plugins as self.ui.document

You might also need some checks like in:

function ReaderStatistics:isDocless() return self.ui == nil or self.ui.document == nil end

so it does not fail and do nothing when in FileManager ?

In onReaderReady I have added:

function CoverImage:onReaderReady(doc_settings) logger.dbg("CoverImage: onDocSettingsLoad") if self.enabled and self.ui and self.ui.document then local lfs = require("libs/libkoreader-lfs")

The plugin is not shown in FileManager, because I have set is_doc_only = true,

plugins/coverimage.koplugin/main.lua

poire-z · 2020-10-22T10:56:09Z

plugins/coverimage.koplugin/main.lua

+
+function CoverImage:addToMainMenu(menu_items)
+    menu_items.coverimage = {
+--        sorting_hint = "device", -- maybe this plugin is better situated in device?


Or in the Screensaver menu ? (Dunno if that's possible)

I do not find the screensaver menu on android (Tolino).
But I could put it in the Gear/Document menu.

There is no screensaver menu on android.

plugins/coverimage.koplugin/main.lua

elvvis · 2020-10-22T13:40:23Z

The plugin will not work on the Tolino. You can select a custom image (in png format) as your screensaver, but if the content of this image is changed later, this will not affect the screensaver (the screensaver image will be converted to jpg format after the png image is selected).
The correct way is to save the book cover as jpg (for Tolino Epos 2 in the directory /data/data/de.telekom.epub/files/lastread.jpg), but for this the device must be rooted.

zwim · 2020-10-22T13:55:28Z

@elvvis: Are you sure? Have you tried it? I am using this plugin for two weeks now and it works on my Epos2.

The plugin will not work on the Tolino. You can select a custom image (in png format) as your screensaver, but if the content of this image is changed later, this will not affect the screensaver (the screensaver image will be converted to jpg format after the png image is selected).

You have to store the image under /sdcard/suspend_others.jpg (use jpg even if the image is png).

The correct way is to save the book cover as jpg (for Tolino Epos 2 in the directory /data/data/de.telekom.epub/files/lastread.jpg), but for this the device must be rooted.

You don't have to root your device for the screensaver!
With this plugin I have my "normal" screensaver image in /sdcard/suspend_others.jpg. If I open a document in KOReader the original image is renamed to /sdcard/suspend_others.jpg.bak and the actual cover is stored as /sdcard/suspend_others.jpg. So I have the book-cover as screensaver. When I end KOReader, the old image is deleted and the backup gets renamed to /sdcard/suspend_others.jpg.

elvvis · 2020-10-22T15:49:02Z

@elvvis: Are you sure? Have you tried it? I am using this plugin for two weeks now and it works on my Epos2.

I didn't know the trick to save the png-image as jpg, but it works great this way.
Fantastic that you wrote this plugin. 👍

plugins/coverimage.koplugin/main.lua

elvvis · 2020-10-22T17:30:46Z

plugins/coverimage.koplugin/main.lua

+            if not lfs.attributes(self.cover_image_path ..".bak") then
+                os.rename(self.cover_image_path, self.cover_image_path .. ".bak" )
+            end
+            Device.screen.bb.writePNG(image, self.cover_image_path, false)


Instead of "Device.screen.bb.writePNG(image, self.cover_image_path, false)" you can use "image:writePNG(self.cover_image_path, false)", so writePNG does not need to be changed in base/ffi/blitbuffer.lua.

@elvvis: As you can see this PR just adds two files. For this PR nothing else has to be changed. So I don't understand your comment about base/ffi/blitbuffer.lua

getCoverPageImage() returns a BB, writePNG is a BB method.

You can just do image:writePNG(self.cover_image_path) ;).

(i.e., Pulling the function out of the Device.screen.bb namespace is extremely roundabout)

@NiLuJe: Ahh, now I see :-)
It works

poire-z · 2020-10-22T19:16:04Z

For the normal non-Android screensaver stuff, we have another option, Exclude this book's cover from screensaver - so when you don't like a cover for a book, you can ignore it and fallback to the other options.
You might want to duplicate it in your plugin (I actually use it quite often), and don't save the cover image on opening when it is set - or restore/save when toggling it.

koreader/frontend/apps/reader/modules/readermenu.lua

Lines 152 to 171 in 99ad13b

    
           if Device:supportsScreensaver() then 
        
               local ss_book_settings = { 
        
                   text = _("Exclude this book's cover from screensaver"), 
        
                   enabled_func = function() 
        
                       return not (self.ui == nil or self.ui.document == nil) 
        
                           and G_reader_settings:readSetting('screensaver_type') == "cover" 
        
                   end, 
        
                   checked_func = function() 
        
                       return self.ui and self.ui.doc_settings and self.ui.doc_settings:readSetting("exclude_screensaver") == true 
        
                   end, 
        
                   callback = function() 
        
                       if Screensaver:excluded() then 
        
                           self.ui.doc_settings:saveSetting("exclude_screensaver", false) 
        
                       else 
        
                           self.ui.doc_settings:saveSetting("exclude_screensaver", true) 
        
                       end 
        
                       self.ui:saveSettings() 
        
                   end, 
        
                   added_by_readermenu_flag = true, 
        
               }

zwim · 2020-10-23T05:40:13Z

@poire-z: Good point, now I can suppress embarrassing images on screen :-)

poire-z · 2020-10-23T06:34:28Z

plugins/coverimage.koplugin/main.lua

+function CoverImage:excluded()
+    local lastfile = G_reader_settings:readSetting("lastfile")
+    local exclude_ss = false -- consider it not excluded if there's no docsetting
+    if DocSettings:hasSidecarFile(lastfile) then
+        local doc_settings = DocSettings:open(lastfile)
+        exclude_ss = doc_settings:readSetting("exclude_cover_image")


This is re-opening/parsing the metatada.zzz.lua, and might be costly. In most (or all, not sure about onCloseDocument) your contexts, you already have self.ui.odc_settings or doc_settings provided, so you can just readSetting("exclude_cover_image") on it - without having to re-open/parse it.

In line 34:
exclude_ss = self.ui.doc_settings:readSetting("exclude_cover_image") brings ./luajit: plugins/coverimage.koplugin/main.lua:35: attempt to index field 'ui' (a nil value)

and
exclude_ss = DocSettings:readSetting("exclude_cover_image")
brings up ./luajit: frontend/docsettings.lua:170: attempt to index field 'data' (a nil value)

So i have combined the old method with self.ui.doc_settings

For the 2nd one:
exclude_ss = DocSettings:readSetting("exclude_cover_image")
DocSettings is a module/class, not an instance, so it has no data, nothing to readerSetting from :)

poire-z · 2020-10-23T10:44:17Z

plugins/coverimage.koplugin/main.lua

+function CoverImage:excluded()
+    local lastfile = G_reader_settings:readSetting("lastfile")
+    local exclude_ss = false -- consider it not excluded if there's no docsetting
+    if DocSettings:hasSidecarFile(lastfile) then
+        if self and self.ui then


No need to check if self (it always exists), I guess you meant if self.ui and self.ui.doc_settings then.

But I still don't like all that :)
It feels none of this is needed, and you don't need to care about lastfile:

in CoverImage:onCloseDocument(), you don't really need to know if excluded: if restore and there's a .bak: restore it.

in CoverImage:onReaderReady(doc_settings), you have the doc_settings, so just read it

If there's some edge case because you call these 2 methods when toggling stuff in the menu, may be you should have 2 other methods: CoverImage:backupPreviousAndCreateNewOne() and CoverImage:restorePreviousIfAny() (with better names :) to do the low level check and action - and onCloseDocument/OnReaderReady/your menu callbacks would do the check they can from what they have - and call the 2 lowlevel methods if stuff should be done.

poire-z

Looks simpler and sane :)

poire-z · 2020-10-24T10:42:53Z

plugins/coverimage.koplugin/main.lua

+    local has_bak = lfs.attributes(self.cover_image_path .. ".bak")
+    -- Delete image if backup exists, the backup could contain a user defined sleep image
+    if lfs.attributes(self.cover_image_path) and has_bak then
+        os.remove(self.cover_image_path)
+    end
+    -- Restore backup if it exists, so we can use the last image.
+    -- On Tolino a user defined /sdcard/suspend_others.jgp can be used as screensaver on system sleep.
+    if has_bak then
+        os.rename(self.cover_image_path .. ".bak", self.cover_image_path)
+    end


Looks like all this can be wrap in a single if has_bak then.
(And may be have self.cover_image_path .. ".bak" in a local variable to avoid doing the concat twice.

About the last comment:

On Tolino a user defined /sdcard/suspend_others.jgp can be used as screensaver on system sleep

You mean one could chose to not have a main image (the one that becomes .bak)? In this case, shouldn't you also os.remove(self.cover_image_path) when has_bak is false ?

Thank you, the has_bak on the remove is wrong.

poire-z · 2020-10-24T10:46:49Z

plugins/coverimage.koplugin/main.lua

+                callback = function()
+                    self.enabled = not self.enabled
+                    G_reader_settings:saveSetting("cover_image_enabled", self.enabled)
+                    G_reader_settings:flush()


Why did you feel the need to add this :flush() ?
It womm flush to disk settings.reader.lua - which shouldn't be needed to be done explicitely. :saveSettings() updates the table in memory, and it will always be flushed with the other stuff when needed (regularly, on switching documents, and always on KOReader exit).

Thank you for your hint. I have used watch -n 0.5 grep cover_image settings.reader.lua to watch changes. With this I noticed, that no changes in settings.reader.lua showed up. On the next start of KOReader the old values where still there. Maybe this was caused by kill of KOReader-emulator (ctrl-c).
Now I have checked this all over again, and could NOT confirm this strange behavior.

You are right, the flush is not necessary.

That's a ~~SIGQUIT~~ SIGINT, so, yeah, a ^C will murder the state, don't do that ;).

We only save the state on graceful exits.

poire-z · 2020-10-24T13:33:47Z

plugins/coverimage.koplugin/main.lua

+    if lfs.attributes(self.cover_image_path) then
+        os.remove(self.cover_image_path)
+    end


As this is always called by onCloseDocument() (if restore=true), if there is no coverimage, this might delete the default image (which would not have been renamed to .bak) ?

poire-z

You must have thought more than I did about all the logic and edge cases - but reading it from a distance, the logic feels a bit fuzzy and unclear. It feels there could be a cleaner and simpler logic to managing all that.

poire-z · 2020-10-24T20:03:16Z

plugins/coverimage.koplugin/main.lua

+local CoverImage = WidgetContainer:new{
+    name = 'coverimage',
+    is_doc_only = true,
+    settings_id = 0,


unused (probably a left over of the copied base plugin)

poire-z · 2020-10-24T20:04:19Z

plugins/coverimage.koplugin/main.lua

+
+function CoverImage:cleanUpImage()
+    if not self.ui.doc_settings:readSetting("exclude_cover_image") == true then
+        local lfs = require("libs/libkoreader-lfs")


Move this lfs at top with the other requires (it's always loaded, so costs nothing even if not used).
(The other one below can then be removed.)

poire-z · 2020-10-24T20:07:06Z

plugins/coverimage.koplugin/main.lua

+        local image = self.ui.document:getCoverPageImage()
+        if image then


Still an issue in onCloseDocument/cleanUpImage() if there were no image here: the one that is os.remove(self.cover_image_path) is actually the main fallback image.

poire-z · 2020-10-24T20:10:11Z

plugins/coverimage.koplugin/main.lua

+                    self.enabled = not self.enabled
+                    G_reader_settings:saveSetting("cover_image_enabled", self.enabled)
+                    if self.enabled then
+                        self.restore = true


Can't one toggle "enabled" while still wanting "restore" to stay false?
I assume the combination of enabled=true and restore=false is when one wants to keep the last book cover as the screensaver when exiting KOReader, or exiting it while in Filebrowser ?

zwim · 2020-10-25T08:48:09Z

You are right, the logic is a bit complicated.
I will let it sit for a while, now.

rola25 · 2020-10-25T09:06:04Z

Does this also work on Tolino firmware 13.2.1?

zwim · 2020-10-25T10:03:22Z

@rola25: Actually I have 14.0.0, so I can not test it on 13.2.1. But the trick with putting a screensaver image in /sdcard/suspend_others.jpg also works on 13.2.1.
So I think, the plugin should work.

On old firmware versions (IIRC 10.0.x) the filename in /sdcard/suspend.jpg (IIRC) was different.

If you try it, could you give me a feedback please?

rola25 · 2020-10-25T10:10:43Z

I can try it. Should I just copy the coverimage.koplugin Folder to /data/data/org.kor..... or do I need anything else? Which Screensaver do I have to choose in the tolinio-settings? Just the tolino-face screensaver?

zwim · 2020-10-25T10:15:52Z

You just have to copy folder coverimage.koplugin in /data/data/.... You find the plugin settings, if you open Menu-Gear-Dokument, when you have a document opened. You won't see it in the filemanager.
You don't have to mess with the Tolino software.

pazos · 2020-10-25T10:24:45Z

On old firmware versions (IIRC 10.0.x) the filename in /sdcard/suspend.jpg (IIRC) was different.

Not sure about the file, but the path is highly specific. For example, in @rola25 logcat

I/KOReader( 5021): Application info {
I/KOReader( 5021):   VM heap: 128MB (normal)
I/KOReader( 5021):   Flags: user.
I/KOReader( 5021):   Paths {
I/KOReader( 5021):     Assets: /data/data/org.koreader.launcher/files
I/KOReader( 5021):     Library: /data/app-lib/org.koreader.launcher-2
I/KOReader( 5021):     Storage: /storage/sdcard1
I/KOReader( 5021):   }
I/KOReader( 5021): }

The proper way of handling that is to use android.getExternalStoragePath(), which will always return a valid path to primary storage. (/storage/sdcard1 in this case). Usually /sdcard is a symlink to that folder, but that's another topic.

zwim · 2020-10-25T10:41:12Z

@pazos: I let the user enter a filename for the image. So the user is responsible to enter a valid path. If the plugin is (ab)used to change the screensaver image, this has to be entered only once (and it is device-specific).

Maybe later, if someone requests, we could improve the dialog for the filename with a path-selector and then we would use `android.getExternalStoragePath()', or we use the filemanager to select the image ...

pazos · 2020-10-25T10:45:54Z

Yeah, I know and I'm fine with your proposal 👍

Maybe later, if someone requests, we could improve the dialog for the filename with a path-selector and then we would use `android.getExternalStoragePath()', or we use the filemanager to select the image ...

You can do a runtime check with Device:isValidPath(path) when the user enters the file path. On the emulator it will return always true. On android it will return true if the path starts with android.getExternalStoragePath()

The filechooser thingy is a bit overkill IMHO.

rola25 · 2020-10-25T10:51:44Z

I tried it, but it didn't work. It creates the file on the right place but it didn't use it, so I made a logcat and it said:
I/PowerManagerService( 2477): Going to sleep by user request...
D/FrontLight( 2477): Light====>SYS. brightness orig 0 conv 0
I/Terry-FB( 2477): strSuspendImgFileName = /storage/sdcard1/suspend.jpg
I/Terry-FB( 2477): strEPubFolder + "/" + strDefaultImgFileName = /data/data/de.telekom.epub/files//suspend.jpg
I/Terry-FB( 2477): strLocaleImgFolder + "/" + strDefaultImgFileName = /system/usr/sleep/drawable-de-nodpi/suspend.jpg
I/Terry-FB( 2477): strEPubFolder + "/" + strChargeImgFileName = /data/data/de.telekom.epub/files//suspend_charging.jpg
I/Terry-FB( 2477): strLocaleImgFolder + "/" + strChargeImgFileName = /system/usr/sleep/drawable-de-nodpi/suspend_charging.jpg
I/Terry-FB( 2477): strLocaleImgFolder + "/" + strFullImgFileName = /system/usr/sleep/drawable-de-nodpi/suspend_batteryfull.jpg
I/DANIEL-FB( 2477): strCurrentImgFileName =============== suspend.jpg
I/FrameBufferEx( 2477): Disp File: /data/data/de.telekom.epub/files/suspend.jpg

So I tried to set it to /sdcard/suspend.jpg, but it also doesn't work ... I just see the tolino face

rola25 · 2020-10-25T10:53:25Z

Perhaps because it has the wrong size?

pazos · 2020-10-25T10:55:43Z

I/Terry-FB( 2477): strSuspendImgFileName = /storage/sdcard1/suspend.jpg

Try that. If that doesn't work it could be that it needs a valid jpg and not a png (or the size, I dunno)

zwim · 2020-10-25T11:23:58Z

The right name of the file is /sdcard/suspend_others.jpg.
And the Tolino must not be connected via usb.
It can be a png named as jpg, size does not matter.

rola25 · 2020-10-25T11:51:32Z

Aaah, it works now, I was connected via ADB+USB, that was the problem. I use /sdcard/suspend.jpg as Cover Image and that works when disconnected from USB

zwim · 2020-10-25T12:28:38Z

@rola25: Good to hear :-)
On my Tolino /sdard/suspend.jpg does not work and on yours it does. Could you please check if suspend_others.jpg works on your device, too?

rola25 · 2020-10-25T13:01:16Z

I just tried it, and it doesn't work with suspend_others.jpg. I have a Toline Epos 1 with Firmware 13.2.1

zwim · 2020-10-25T18:18:42Z

@pazos: I have a logical much easier implementation. The only "drawback" is, that the user has to enter the file name of his default screensaver image, which is chosen, when the Cover Image is deleted onDocumentClose.

The UI would look like this

plugins/coverimage.koplugin/main.lua

NiLuJe · 2020-11-09T19:33:20Z

It hasn't been merged yet, so, no?

sndwichm4n · 2020-11-09T19:51:33Z

Ok, I am no programmer. When is the merging?

sndwichm4n · 2020-11-09T19:53:28Z

I ask because pazos has approved and the plugin tool must be awesome. :)

zwim · 2020-11-09T20:07:09Z

I have added a short description of the usage of this plugin on
https://github.com/koreader/koreader/wiki/Android-tips-and-tricks

plugins/coverimage.koplugin/main.lua

Galunid

LGTM
@pazos Is there any way to broadcast android Intent from lua? I took a look at Onyx SDK set cover and it doesn't seem too hard to add this, except for broadcasting the intent. The part of interest in the demo.

pazos · 2020-11-09T21:06:03Z

I have added a short description of the usage of this plugin on
https://github.com/koreader/koreader/wiki/Android-tips-and-tricks

Thanks for the wiki stuff @zwim. I think it is better to document it on a separate plugin page (The text and all the samples are ok) and leave Android-tips-and-tricks for platform code.

pazos · 2020-11-09T21:10:58Z

@pazos Is there any way to broadcast android Intent from lua? I took a look at Onyx SDK set cover and it doesn't seem too hard to add this, except for broadcasting the intent. The part of interest in the demo.

Yup. There are plenty of samples in the code: a dict lookup, open a link in the browser, start the EPD test activity ... all use startActivity. There's also a wrapper called startActivityIfSafe that queries the packageManager before calling startActivity, so it is only called if there's a package able to resolve the intent. It should be useful to prevent ActivityNotFound exceptions.

Still not sure about your intent with the intent :)

pazos · 2020-11-09T21:17:11Z

@Galunid: we don't use sendBroadcast anywhere on the code. After a quick read of https://developer.android.com/reference/android/content/Context#sendBroadcast(android.content.Intent) it looks like sendBroadcast(intent) is the same than startActivity(intent). The former is used to communicate with Broadcast receivers and the later is to communicate with activities.

ptrm · 2020-11-11T09:23:15Z

Is this plugin checking for android or disabling itself because of some deps furthers down the code, or is there a chance it might work for Pocketbooks (they also can have an image specified for screensaver)?

Frenzie · 2020-11-11T10:50:52Z

Is this plugin checking for android

Yes.

is there a chance it might work for Pocketbooks

Well… also yes? ;-P Depending on what PB requires, only minimal adjustments may be needed.

zwim · 2020-11-11T10:56:25Z

Is this plugin checking for android or disabling itself because of some deps furthers down the code, or is there a chance it might work for Pocketbooks (they also can have an image specified for screensaver)?

All the plugin does, is to save the cover to a certain file (it must be in a place which is writeable for KOReader) and restore a fallback image file on close if wanted.

There is no Android mystery hidden in it.

As I don't have a pocketbook I can not test if it works there. But you can test it. Just disable lines 3-5 on plugins/coverimage.koplugin/main.lua and try it out.

I would be interested in the results.

ptrm · 2020-11-11T17:54:23Z

The plugin itself works very well. However, the book cover ~~location~~ PB system feature requires the file to be in... BMP format 😁. Below are the cover file dumps before and after using the plugin. Png is not recognised and results in the generic "Touch HD 3" screen with features listed.

On the other hand, trying to use a custom image as power down logo also ezports the image to tge system/logo dir as BMP, so without BMP support the pkugin seems unusable on PocketBooks 😁 On which I don't insist, but if it's a matter of a single small dependency, that would be great :)

That being said, Pocketbook has a cool feature with it's native reader to show last read page during boot, so you get to the most recent book quickly:

This might be a handy feature on Android as a screensaver, too, with just a screenshot instead of a cover.

NiLuJe · 2020-11-11T18:40:25Z

IIRC, we don't currently have anything that supports writing BMP files.

On the other hand, BMP is a pretty "dumb" format, c.f., stbiw, so someone motivated enough should be able to whip up something via FFI fairly quickly.

Frenzie · 2020-11-11T20:16:55Z

Maybe PB comes with a built-in utility like ImageMagick for such a conversion? Also, I don't know much about BMP files besides having used 'em in Microsoft Paintbrush/Paint when I was little. If they're mostly compatible with PNM for example we already have MuPDF.

zwim · 2020-11-11T20:58:40Z

Couldn't we use the example of lodepng for creating BMP files:
https://raw.githubusercontent.com/lvandeve/lodepng/master/examples/example_png2bmp.cpp

If no one else stands up, I could look into it more deeply tomorrow.

zwim · 2020-11-12T09:28:01Z

I have done a quick test with https://github.com/nothings/stb and compiled a command line tool (Android, Emulator) to convert between bmp, jpg and png. For jpg even a compression (quality) setting is possible.

It seems to be usable on my Tolino.

usage: image-convert infile outfile format quality infile and outfile can be the same.

As I am not familiar to integrate a new library or C-functions to KOReader, I will definitively stop work here.
I hope someone wants to continue from here.

I could integrate the new function in the cover-image plugin.

/*
 * simple programm to convert files between bmp, jpg, png
 * Autor: @zwim
 * thanks to https://github.com/nothings/stb 
 *
 * Date: 11/12/2020
 * 
*/

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
 
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include "stb_image_write.h"
 
 int main(int argc, char *argv[]) {
    int width, height, channels;
    unsigned char *img;

    if ( argc < 5 ) {
        printf("usage: image-convert infile outfile format quality\n format can be: bmp, jpg, png\nquality is only valid for jpg: 1-100\n");
        exit(1);
    }

    img = stbi_load(argv[1], &width, &height, &channels, 0);

    if(img == NULL) {
        printf("Error in loading the image\n");
        exit(1);
    }
    printf("Loaded image with a width of %dpx, a height of %dpx and %d channels\n", width, height, channels);

    if ( strcasecmp(argv[3], "PNG" ) == 0 )
        stbi_write_png(argv[2], width, height, channels, img, width * channels);
    else if ( strcasecmp( argv[3], "JPG" ) == 0 )
        stbi_write_jpg(argv[2], width, height, channels, img, atoi(argv[4]) );
    else if ( strcasecmp( argv[3], "BMP" ) == 0 )
        stbi_write_bmp(argv[2], width, height, channels, img);

    stbi_image_free(img);    
    return 0; 
}

Frenzie · 2020-11-12T09:50:45Z

Couldn't we use the example of lodepng for creating BMP files:

I didn't realize the format was that simple, but I suppose it doesn't have compression. In that case I'd suggest simply popping in https://github.com/luapower/bmp/blob/25733a99f077bde8215d7d7939c96ea2371659bc/bmp.lua

zwim · 2020-11-12T20:06:12Z

simple, but I suppose it doesn't have compression.

In my younger days I was forced quite often to use bmp. It was a really dump format and had no compression. Don't know, if that was added later.

But I would prefer the stb solution, as we could also save images in the jpg format, which would save quite a bit of flash.
You can see a short demonstration (Android, Linux) on https://github.com/zwim/image-converter.

Frenzie · 2020-11-12T20:47:07Z

But I would prefer the stb solution, as we could also save images in the jpg format, which would save quite a bit of flash.

Er, if PB takes jpeg then we don't need any extra anything. ;-)

Frenzie · 2020-11-19T11:21:42Z

plugins/coverimage.koplugin/main.lua

+                checked_func = function()
+                    return lfs.attributes(self.cover_image_fallback_path, "mode") == "file"
+                end,
+                help_text =  _("File to use when no cover is wanted (found ???) or book is excluded.\nLeave this blank to turn off the fallback image."),


@zwim Leftover draft of some sort, will you submit a PR to fix it?

Oh, thank you.

Yes, we can delete the help_text, as the dialog shows instructions.
But there is a minor problem showing a wrong info message, when fallback_image is an empty string.

I do a PR a bit later, today.

Cf. #6813 (comment)

poire-z reviewed Oct 22, 2020

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Galunid approved these changes Nov 9, 2020

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pazos added the Android label Nov 10, 2020

pazos merged commit 926e7dd into koreader:master Nov 10, 2020

zwim deleted the coverimage branch November 10, 2020 14:19

Frenzie reviewed Nov 19, 2020

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Frenzie pushed a commit that referenced this pull request Nov 20, 2020

Remove leftover and correct info message on empty fallback (#6897)

2785f0d

Cf. #6813 (comment)

Frenzie mentioned this pull request Nov 20, 2020

Remove leftover and correct info message on empty fallback #6897

Merged

This was referenced Nov 21, 2020

Add a function to write BMP-files koreader/koreader-base#1233

Merged

Add functionality to write BMP-Images in Cover-Image #6904

Merged

poire-z mentioned this pull request Jan 16, 2021

Custom folder for saving book cover #7151

Closed

gbyl mentioned this pull request Apr 4, 2021

CoverImage plugin: Remarkable-specific alternative #7506

Closed

	-- Allow others to change settings based on external factors
	-- Must be called after plugins are loaded & before setting are read.
	self:handleEvent(Event:new("DocSettingsLoad", self.doc_settings, self.document))
	-- we only read settings after all the widgets are initialized
	self:handleEvent(Event:new("ReadSettings", self.doc_settings))

	for _,v in ipairs(self.postInitCallback) do
	v()
	end
	self.postInitCallback = nil

	-- Now that document is loaded, store book metadata in settings
	-- (so that filemanager can use it from sideCar file to display
	-- Book information).
	self.doc_settings:saveSetting("doc_props", self.document:getProps())

	-- After initialisation notify that document is loaded and rendered
	-- CREngine only reports correct page count after rendering is done
	-- Need the same event for PDF document
	self:handleEvent(Event:new("ReaderReady", self.doc_settings))

		local image = self.ui.document:getCoverPageImage()
		if image then

Plugin for saving the cover image to file #6813

Plugin for saving the cover image to file #6813

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