Allow mods to contain a "preview.png" file for visual indication

core/src/com/unciv/logic/multiplayer/storage/OnlineMultiplayerServer.kt

@@ -31,17 +31,12 @@ class OnlineMultiplayerServer(
         val authHeader = if (authenticationHeader == null) {
             val settings = UncivGame.Current.settings.multiplayer
             mapOf("Authorization" to settings.getAuthHeader())
-        } else {
+        } else authenticationHeader
-            authenticationHeader
-        }
 
-        return if (serverUrl == Constants.dropboxMultiplayerServer) {
+        return if (serverUrl == Constants.dropboxMultiplayerServer) DropBox
-            DropBox
+        else UncivServerFileStorage.apply {
-        } else {
+            serverUrl = this@OnlineMultiplayerServer.serverUrl
-            UncivServerFileStorage.apply {
+            this.authHeader = authHeader
-                serverUrl = this@OnlineMultiplayerServer.serverUrl
-                this.authHeader = authHeader
-            }
         }
     }
 

core/src/com/unciv/models/ruleset/Ruleset.kt

@@ -55,6 +55,7 @@ class ModOptions : IHasUniques {
 
     var lastUpdated = ""
     var modUrl = ""
+    var defaultBranch = "master"
     var author = ""
     var modSize = 0
     var topics = mutableListOf<String>()

core/src/com/unciv/ui/screens/pickerscreens/GitHub.kt

@@ -2,6 +2,7 @@ package com.unciv.ui.screens.pickerscreens
 
 import com.badlogic.gdx.Files
 import com.badlogic.gdx.files.FileHandle
+import com.badlogic.gdx.graphics.Pixmap
 import com.unciv.json.fromJsonFile
 import com.unciv.json.json
 import com.unciv.logic.BackwardCompatibility.updateDeprecations
@@ -20,6 +21,7 @@ import java.io.InputStream
 import java.io.InputStreamReader
 import java.net.HttpURLConnection
 import java.net.URL
+import java.nio.ByteBuffer
 import java.util.zip.ZipEntry
 import java.util.zip.ZipFile
 
@@ -250,6 +252,15 @@ object Github {
         return null
     }
 
+    fun tryGetPreviewImage(modUrl:String, defaultBranch: String): Pixmap?{
+        val fileLocation = "$modUrl/$defaultBranch/preview.png"
+            .replace("github.com", "raw.githubusercontent.com")
+        val file = download(fileLocation) ?: return null
+        val byteArray = file.readBytes()
+        val buffer = ByteBuffer.allocateDirect(byteArray.size).put(byteArray).position(0)
+        return Pixmap(buffer)
+    }
+
     class Tree {
 
         class TreeFile {
@@ -385,6 +396,7 @@ object Github {
         val modOptionsFile = modFolder.child("jsons/ModOptions.json")
         val modOptions = if (modOptionsFile.exists()) json().fromJsonFile(ModOptions::class.java, modOptionsFile) else ModOptions()
         modOptions.modUrl = repo.html_url
+        modOptions.defaultBranch = repo.default_branch
         modOptions.lastUpdated = repo.pushed_at
         modOptions.author = repo.owner.login
         modOptions.modSize = repo.size

core/src/com/unciv/ui/screens/pickerscreens/ModManagementScreen.kt

@@ -2,9 +2,11 @@ package com.unciv.ui.screens.pickerscreens
 
 import com.badlogic.gdx.Gdx
 import com.badlogic.gdx.graphics.Color
+import com.badlogic.gdx.graphics.Texture
 import com.badlogic.gdx.scenes.scene2d.Actor
 import com.badlogic.gdx.scenes.scene2d.Touchable
 import com.badlogic.gdx.scenes.scene2d.ui.Button
+import com.badlogic.gdx.scenes.scene2d.ui.Image
 import com.badlogic.gdx.scenes.scene2d.ui.Label
 import com.badlogic.gdx.scenes.scene2d.ui.ScrollPane
 import com.badlogic.gdx.scenes.scene2d.ui.Table
@@ -44,8 +46,8 @@ import com.unciv.ui.screens.basescreen.BaseScreen
 import com.unciv.ui.screens.basescreen.RecreateOnResize
 import com.unciv.ui.screens.mainmenuscreen.MainMenuScreen
 import com.unciv.ui.screens.pickerscreens.ModManagementOptions.SortType
-import com.unciv.utils.Log
 import com.unciv.utils.Concurrency
+import com.unciv.utils.Log
 import com.unciv.utils.launchOnGLThread
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.isActive
@@ -347,7 +349,7 @@ class ModManagementScreen(
      * @param repo: the repository instance as received from the GitHub api
      */
     private fun addModInfoToActionTable(repo: Github.Repo) {
-        addModInfoToActionTable(repo.html_url, repo.pushed_at, repo.owner.login, repo.size)
+        addModInfoToActionTable(repo.html_url, repo.default_branch, repo.pushed_at, repo.owner.login, repo.size)
     }
     /** Recreate the information part of the right-hand column
      * @param modName: The mod name (name from the RuleSet)
@@ -358,11 +360,13 @@ class ModManagementScreen(
             modOptions.modUrl,
             modOptions.lastUpdated,
             modOptions.author,
+            modOptions.defaultBranch,
             modOptions.modSize
         )
     }
     private fun addModInfoToActionTable(
         repoUrl: String,
+        default_branch: String,
         updatedAt: String,
         author: String,
         modSize: Int
@@ -371,6 +375,22 @@ class ModManagementScreen(
 
         // Display metadata
 
+        val imageHolder = Table()
+        Concurrency.run {
+            val imagePixmap = Github.tryGetPreviewImage(repoUrl, default_branch) ?: return@run
+            Concurrency.runOnGLThread {
+                val largestImageSize = max(imagePixmap.width, imagePixmap.height)
+                val cell = imageHolder.add(Image(Texture(imagePixmap)))
+
+                val maxAllowedImageSize = 200f
+                if (largestImageSize > maxAllowedImageSize) {
+                    val resizeRatio = maxAllowedImageSize / largestImageSize
+                    cell.size(imagePixmap.width * resizeRatio, imagePixmap.height * resizeRatio)
+                }
+            }
+        }
+        modActionTable.add(imageHolder).row()
+
 
         if (author.isNotEmpty())
             modActionTable.add("Author: [$author]".toLabel()).row()

docs/Modders/Mods.md

@@ -115,6 +115,8 @@ When loading a mod, it needs to be in its own folder in `/mods` - this is how yo
 
 ## Other
 
+You can add an image that will be displayed to users in the mod management by adding a "preview.png" file.
+
 Existing mods can be found [here](https://github.com/topics/unciv-mod)!
 
 A list of uniques and how to use them can be found [here](Unique-parameters.md)!