Hello Kin Could you please guide me on what you did? Thanks Anand
On Tue, 17 Sept, 2024, 8:00 am Kin, <geniusw...@qq.com> wrote: > I can do it without libgphoto. Compiling libgphoto on an iPad or iOS is > impossible. I tried, but it failed. So, I found an alternative solution. > > ------------------ Original ------------------ > *From:* Anand Walvekar <anand.walve...@onemorehustle.com> > *Date:* Tue,Sep 17,2024 9:41 AM > *To:* Ole Aamot <o...@gnu.org> > *Cc:* gphoto-devel <gphoto-devel@lists.sourceforge.net>, Marcus Meissner < > mar...@jet.franken.de> > *Subject:* Re: [gphoto-devel] iPad USB Support > > Thank you. libgphoto2 depends on other dylb. Compilation seems to be a task > > Regards > Anand > > On Tue, 17 Sept, 2024, 6:18 am Ole Aamot, <o...@gnu.org> wrote: > >> Implement libgphoto2 Camera Driver for iPad USB >> >> Implementing a camera driver using `libgphoto2` and `libusb` for iPadOS >> is complex, particularly due to iOS's restrictions on direct USB access. >> However, I can guide you through writing code that integrates `libgphoto2` >> and `libusb` in a general way, while recognizing the unique hurdles on >> iPadOS. >> >> Here’s an example that assumes you're able to compile `libusb` and >> `libgphoto2` for iOS. This example sets up a simple app that uses a camera >> connected via USB. Keep in mind that on iPad, actual USB access will likely >> be limited unless you have the proper entitlements from Apple. >> >> ### 1. **Cross-Compiling `libgphoto2` and `libusb`** >> >> First, you need to cross-compile `libgphoto2` and `libusb` for iPad. This >> process involves setting up a toolchain and using CMake to build the >> libraries as static libraries for ARM architecture. Here’s a guide for that >> process: >> >> ```bash >> # Install dependencies (on macOS) >> brew install automake libtool cmake >> >> # Clone libgphoto2 >> git clone https://github.com/gphoto/libgphoto2.git >> cd libgphoto2 >> >> # Build for iOS (ensure you have an iOS toolchain configured) >> ./autogen.sh >> ./configure --host=arm-apple-darwin >> make >> ``` >> >> ### 2. **Basic iOS App Setup (Swift + Objective-C)** >> >> In Xcode, create a new iOS project in Swift, then add the compiled static >> libraries for `libgphoto2` and `libusb`. >> >> ### 3. **Bridging Header for `libgphoto2` in Swift** >> >> Since `libgphoto2` is a C library, you will need to create a bridging >> header to use it within a Swift-based iOS project. >> >> **Create `gphoto2_bridge.h` (Objective-C bridging header):** >> >> ```objective-c >> // gphoto2_bridge.h >> #import <Foundation/Foundation.h> >> >> #ifdef __cplusplus >> extern "C" { >> #endif >> >> #include <gphoto2/gphoto2.h> >> >> int detect_camera(GPContext *context); >> >> #ifdef __cplusplus >> } >> #endif >> ``` >> >> **Create `gphoto2_bridge.c` (C code that interacts with libgphoto2):** >> >> ```c >> #include "gphoto2_bridge.h" >> >> int detect_camera(GPContext *context) { >> int ret; >> Camera *camera; >> GPPortInfoList *portinfolist = NULL; >> CameraAbilitiesList *abilities = NULL; >> >> ret = gp_camera_new(&camera); >> if (ret < GP_OK) return ret; >> >> ret = gp_abilities_list_new(&abilities); >> if (ret < GP_OK) return ret; >> >> ret = gp_port_info_list_new(&portinfolist); >> if (ret < GP_OK) return ret; >> >> ret = gp_abilities_list_load(abilities, context); >> if (ret < GP_OK) return ret; >> >> ret = gp_port_info_list_load(portinfolist); >> if (ret < GP_OK) return ret; >> >> return GP_OK; >> } >> ``` >> >> ### 4. **Swift Code (ViewController.swift)** >> >> This Swift code will interact with the `libgphoto2` library via the >> bridging header. >> >> ```swift >> import UIKit >> >> class ViewController: UIViewController { >> >> override func viewDidLoad() { >> super.viewDidLoad() >> >> // Call the C function to detect the camera >> detectCamera() >> } >> >> func detectCamera() { >> // Create the GPContext >> let context = createGPContext() >> >> // Call the detect_camera function from the C library >> let result = detect_camera(context) >> if result == 0 { >> print("Camera detected successfully!") >> } else { >> print("Failed to detect camera.") >> } >> } >> >> // GPContext is a placeholder for actual libgphoto2 context management >> func createGPContext() -> OpaquePointer? { >> let context: OpaquePointer? = nil >> // You'd need to properly initialize the context here >> return context >> } >> } >> ``` >> >> ### 5. **Handling USB Access (libusb)** >> >> You would similarly add a bridging header and interact with `libusb`. >> However, due to iOS restrictions, `libusb` is likely to require >> entitlements to access USB devices directly. >> >> **Create `usb_bridge.h` (bridging header for libusb):** >> >> ```objective-c >> #import <Foundation/Foundation.h> >> >> #ifdef __cplusplus >> extern "C" { >> #endif >> >> #include <libusb-1.0/libusb.h> >> >> int initialize_usb(); >> >> #ifdef __cplusplus >> } >> #endif >> ``` >> >> **Create `usb_bridge.c`:** >> >> ```c >> #include "usb_bridge.h" >> >> int initialize_usb() { >> libusb_context *ctx = NULL; >> int r = libusb_init(&ctx); >> if (r < 0) { >> return r; >> } >> >> // Find connected USB devices >> libusb_device **devs; >> ssize_t cnt = libusb_get_device_list(ctx, &devs); >> if (cnt < 0) return (int)cnt; >> >> libusb_free_device_list(devs, 1); >> libusb_exit(ctx); >> return 0; >> } >> ``` >> >> ### 6. **Swift Code for USB Initialization** >> >> ```swift >> func initializeUSB() { >> let result = initialize_usb() >> if result == 0 { >> print("USB initialized successfully.") >> } else { >> print("Failed to initialize USB.") >> } >> } >> ``` >> >> ### 7. **Handle iOS Permissions and Testing** >> >> Given iOS’s restrictions on USB access, you’ll need to consider using >> Apple’s `ExternalAccessory` framework for official USB hardware access. >> Alternatively, if the camera supports wireless (e.g., Wi-Fi), you can >> communicate over the network to avoid USB restrictions altogether. >> >> Testing on an actual device will be critical because the iOS Simulator >> does not support USB or accessory connections. >> >> ### 8. **Next Steps and Entitlements** >> >> - **Request Entitlements**: To access USB devices, you will likely need >> to join Apple's MFi (Made for iPhone/iPad) program and request the >> necessary entitlements. >> - **Test and Debug**: Testing on actual hardware will help you understand >> how the app behaves when communicating with a camera via USB. >> >> Would you like assistance with any specific part of the code, or do you >> need further guidance on handling USB in iOS? >> >> Sincerely, >> >> >> Ole Aamot >> >> o...@aamot.org >> >> www.aamot.org >> >> +47-4173-2002 >> >> >> >> On Mon, Sep 16, 2024 at 7:28 AM Anand Walvekar < >> anand.walve...@onemorehustle.com> wrote: >> >>> Thank you Ole for your time. >>> >>> ChatGPT seems to be more descriptive to you 😊 >>> >>> I have been trying to recompile the libgphoto2 and its dependencies with >>> clang and linking with iOS framework. Clang treats warning as errors and it >>> needs source code changes. Also libgphoto2 loads dylb from system path >>> which also needs to be taken into account. >>> >>> Over it's not straightforward. >>> >>> Thank you >>> Anand >>> >>> >>> >>> On Mon, 16 Sept, 2024, 3:37 am Ole Aamot, <o...@gnu.org> wrote: >>> >>>> ChatGPT gave this answer: >>>> >>>> To implement a **libgphoto2** camera driver for an iPad over USB, you >>>> would need to address several layers of challenges including hardware >>>> support, communication protocols, and OS-level restrictions. Here's a >>>> high-level approach to guide the development: >>>> >>>> ### Steps to Implement libgphoto2 Camera Driver for iPad USB >>>> >>>> #### 1. **Understand the iPad USB Accessory Framework** >>>> - Apple provides the **External Accessory framework** to communicate >>>> with external hardware. However, it's quite restrictive and typically meant >>>> for licensed manufacturers. >>>> - iOS and iPadOS don't natively support generic USB drivers like on >>>> Linux or Windows, so the challenge is creating a bridge for libgphoto2 to >>>> access the camera hardware over USB. >>>> - Check if the camera can be accessed via a **Camera Connection >>>> Kit** or Lightning-to-USB adapter and whether it's recognized as a USB >>>> accessory. >>>> >>>> #### 2. **Develop a Custom iOS App** >>>> - You would likely need to create a custom iOS application using >>>> **Swift** or **Objective-C** to interface with the camera. >>>> - Investigate the **USBDevice** API (for iOS 16+) if available, >>>> which offers more flexibility in accessing USB devices directly on >>>> iOS/iPadOS. >>>> - Use the **USB Accessory Mode** for detecting connected devices. >>>> >>>> #### 3. **Compile libgphoto2 for iOS** >>>> - Libgphoto2 is built for POSIX systems, so you’ll need to >>>> cross-compile it for iOS using tools like **Xcode** or **CMake** with >>>> specific target flags for ARM architecture. >>>> - It may require modifications to libgphoto2 code to interact with >>>> iOS's unique environment and APIs. >>>> - Remove or adapt dependencies in libgphoto2 that might not be >>>> supported by iOS (such as certain POSIX libraries). >>>> >>>> #### 4. **USB Communication Bridge** >>>> - Libgphoto2 communicates with cameras using PTP (Picture Transfer >>>> Protocol) or proprietary protocols over USB. >>>> - Implement a communication bridge between libgphoto2 and iOS's USB >>>> interface. This may involve writing code to mimic Linux's USB driver >>>> behavior within the iOS app. >>>> - The **libusb** library might also need to be ported or modified >>>> for iOS to enable USB communication, since it is widely used by libgphoto2. >>>> >>>> #### 5. **Sandboxing and Permissions** >>>> - iOS has strict sandboxing. Ensure that your app requests the >>>> necessary permissions to communicate with USB devices and interact with >>>> external hardware. >>>> - Add necessary entitlements in the **Info.plist** file, like >>>> `com.apple.external-accessory` or `com.apple.developer.usb`. >>>> >>>> #### 6. **Testing with Different Cameras** >>>> - Libgphoto2 supports a wide range of cameras, so you'll need to >>>> test with specific camera models. >>>> - Ensure that the camera can be recognized by the app, and you can >>>> trigger functions like capturing images, downloading files, or controlling >>>> camera settings. >>>> >>>> #### 7. **Distributing the App** >>>> - If the app is for personal use, you can sideload it to your iPad >>>> using Xcode and a developer account. >>>> - If the goal is broader distribution, you would need to ensure >>>> compliance with Apple's guidelines, especially for apps interacting with >>>> external hardware. >>>> >>>> ### Challenges >>>> - **Apple's closed ecosystem**: iOS is not designed to be an open >>>> system like Linux, so you will face challenges accessing hardware. >>>> - **Licensing**: If this driver is to be distributed, you may need >>>> Apple's MFi (Made for iPhone/iPad) certification for USB accessory >>>> communication. >>>> >>>> ### Summary >>>> This task involves cross-compiling libgphoto2 for iOS, interfacing with >>>> iPad USB APIs, and overcoming OS-level restrictions. Starting with Apple’s >>>> USBDevice APIs and building a custom iOS app to bridge libgphoto2’s >>>> functionality is the best approach. You will likely need to experiment with >>>> lower-level hardware protocols and iOS permissions to make it work >>>> effectively. >>>> >>>> Sincerely, >>>> >>>> >>>> Ole Aamot >>>> >>>> o...@aamot.org >>>> >>>> www.aamot.org >>>> >>>> +47-4173-2002 >>>> >>>> >>>> >>>> On Tue, Sep 10, 2024 at 9:11 AM Marcus Meissner <mar...@jet.franken.de> >>>> wrote: >>>> >>>>> Hi, >>>>> >>>>> On Sun, Sep 08, 2024 at 07:21:03PM +0530, Anand Walvekar wrote: >>>>> > Hi Team >>>>> > Hope you are doing well. >>>>> > >>>>> > I need your help to integrate libgphoto2 in iPad application. Could >>>>> you >>>>> > please share me few links which I can try it out. >>>>> > >>>>> > Thank you >>>>> > Anand >>>>> >>>>> This likely means the iPad as USB Host for cameras? >>>>> >>>>> I am not familar with either iPad or if iPad USB-Host is even possible, >>>>> perhaps someone else knows it :/ >>>>> >>>>> Ciao, Marcus >>>>> >>>>> >>>>> _______________________________________________ >>>>> Gphoto-devel mailing list >>>>> Gphoto-devel@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/gphoto-devel >>>>> >>>>
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