Impl Image.load & Add example for Backend.setIcons

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "external/cimgui"]
 	path = external/cimgui
 	url = https://github.com/cimgui/cimgui
+[submodule "external/stb"]
+	path = external/stb
+	url = https://github.com/nothings/stb.git

CMakeLists.txt

@@ -21,6 +21,8 @@ file(GLOB IMGUI_SOURCES
 	${IMGUI_TABLES_SOURCE}
     # cimgui struct accessor wrappers
     ${CMAKE_CURRENT_SOURCE_DIR}/c_src/cimgui_struct_accessors.c
+    # image loading
+    ${CMAKE_CURRENT_SOURCE_DIR}/c_src/load_image.c
 )
 
 set(IMGUI_STATIC "no" CACHE STRING "Build as a static library")
@@ -97,6 +99,7 @@ target_include_directories(${IMGUI4CJ_LIB} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/c_
 target_include_directories(${IMGUI4CJ_LIB} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/external/cimgui)
 target_include_directories(${IMGUI4CJ_LIB} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/external/cimgui/generator/output)
 target_include_directories(${IMGUI4CJ_LIB} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/external/cimgui/imgui)
+target_include_directories(${IMGUI4CJ_LIB} PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/external/stb)
 
 if (IMGUI4CJ_GLFW_OPENGL3_BACKEND)
     target_compile_definitions(${IMGUI4CJ_LIB} PUBLIC IMGUI4CJ_GLFW_OPENGL3_BACKEND=1)

c_src/load_image.c

@@ -0,0 +1,17 @@
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+#include "imgui4cj.h"
+
+#include <assert.h>
+
+// foreign func imgui4cj_loadImage(result: CPointer<CImage>, filename: CString, pErrMsg: CPointer<CPointer<UInt8>>): Int32
+IMGUI4CJ_API int imgui4cj_loadImage(CImage *result, const char *filename, const char ** pErrMsg) {
+    assert(result && filename && pErrMsg);
+
+    int channels;
+    if ((result->pixels = stbi_load(filename, &result->width, &result->height, &channels, 4)) == NULL) {
+        *pErrMsg = stbi_failure_reason();
+        return -1;
+    }
+    return 0;
+}

examples/helloworld/src/main.cj

@@ -1,6 +1,12 @@
 package helloworld
 
+import std.fs.Path
 import imgui4cj.*
+import imgui4cj.utils
+
+func getAssetsDirectory() {
+    return Path("${Path(@sourceFile()).directoryName}/../assets").toCanonical()
+}
 
 main(): Int64 {
     let clickCount = i64(0)
@@ -24,7 +30,9 @@ main(): Int64 {
     )
 
     let backend = getBackend(GLFWOpenGL3)
-    backend.createWindow("Hello IMGUI4CJ", 800, 600).setKeyCallback {
+    backend.createWindow("Hello IMGUI4CJ", 800, 600)
+    .setIcons([utils.Image.load(getAssetsDirectory().join("logo.jpg"))])
+    .setKeyCallback {
         key: Key, _: Int32, action: KeyAction, _: ModifierKey =>
         // Check key `space`
         if (key == KEY_SPACE && action == KEY_PRESS) {

src/backends/glfw_opengl3_backend.cj

@@ -477,7 +477,7 @@ class GLFWOpenGL3Backend <: Backend {
             try (r = LibC.malloc<CImage>(count: icons.size).asResource()) {
                 let pCImage = r.value
                 for (icon in icons) {
-                    pCImage.write(icon.toCImage())
+                    pCImage.write(icon.getCImage())
                 }
                 imgui4cj_glfwSetWindowIcon(glfwWindowInstance, Int32(icons.size), r.value)
             }

src/utils/image.cj

@@ -1,59 +1,42 @@
 package imgui4cj.utils
 
-import std.fs.File
-import std.io.InputStream
-import std.collection.ArrayList
+import std.fs.Path
 
-// TODO: Replace Image and related functions with std/3rd library used to process image
+foreign func imgui4cj_loadImage(result: CPointer<CImage>, filename: CString, pErrMsg: CPointer<CPointer<UInt8>>): Int32
 
 @C
-public struct CImage {
+protected struct CImage {
     var width: Int32 = 0
     var height: Int32 = 0
-    var pixels: CPointer<Byte> = CPointer<Byte>()
-
-    public func release() {
-        unsafe { LibC.free<Byte>(pixels) }
-    }
+    var pixels: CPointer<UInt8> = CPointer<UInt8>()
 }
 
-public struct Image {
-    var width: Int32 = 0
-    var height: Int32 = 0
-    var pixels: ArrayList<Byte> = ArrayList<Byte>([])
-
-    public func toCImage(): CImage {
-        var result = CImage()
-        result.width = width
-        result.height = height
-        result.pixels = unsafe { LibC.malloc<Byte>(count: pixels.size) }
-
-        unsafe { // Copy from pixels to result.pixels
-            var p = result.pixels
-            for (byte in pixels) {
-                p.write(byte)
-                p += 1
-            }
-        }
+public class Image {
+    private Image(private let cImage: CImage) {
+    }
 
-        return result
+    ~init() {
+        unsafe { LibC.free<UInt8>(cImage.pixels) }
     }
-}
 
-public func tryLoadImage(_: InputStream): ?Image {
-    // TODO: Impt it: read many image formats as pixels
-    throw UnsupportedException("to be implemented")
-}
+    protected func getCImage(): CImage {
+        return cImage
+    }
 
-public func tryLoadImage(filename: String): ?Image {
-    try (fp = File.openRead(filename)) {
-        return tryLoadImage(fp)
+    public static func load(filename: Path): Image {
+        return load(filename.toString())
     }
-    return None
-}
 
-public func loadImage(filename: String): Image {
-    return tryLoadImage(filename).getOrThrow {
-        IllegalArgumentException("invalid image file: ${filename}")
+    public static func load(filename: String): Image {
+        try (filenameRes = unsafe { LibC.mallocCString(filename) }.asResource()) {
+            var cImage: CImage = CImage()
+            var errMsg: CPointer<UInt8> = CPointer<UInt8>()
+            let err = unsafe { imgui4cj_loadImage(inout cImage, filenameRes.value, inout errMsg) }
+            if (err != 0) {
+                throw IllegalArgumentException("Load image ${filename} failed: ${CString(errMsg)}")
+            }
+            return Image(cImage)
+        }
+        throw IllegalStateException("illegal state")
     }
 }