Bitmap: implement pixel buffer access

For GPU textures, the GdkTextureDownloader will take care of format
conversions, so the application never sees the actual format.

If the application calls AndroidBitmap_unlockPixels(), the texture is
converted into a GdkMemoryTexture and can be accessed zero copy.
This commit is contained in:
Julian Winkler
2024-12-22 10:20:50 +01:00
parent 7695aadf91
commit 260821d68c
4 changed files with 130 additions and 21 deletions

View File

@@ -1,5 +1,6 @@
#include <gtk/gtk.h>
#include <gdk/gdk.h>
#include <jni.h>
#include <stdio.h>
// FIXME: put the header in a common place
#include "../api-impl-jni/defines.h"
@@ -14,19 +15,67 @@ struct AndroidBitmapInfo {
uint32_t flags;
};
int AndroidBitmap_getInfo(JNIEnv* env, jobject bitmap, struct AndroidBitmapInfo *info) {
GdkPixbuf *pixbuf = _PTR(_GET_LONG_FIELD(bitmap, "pixbuf"));
info->width = gdk_pixbuf_get_width(pixbuf);
info->height = gdk_pixbuf_get_height(pixbuf);
info->stride = gdk_pixbuf_get_rowstride(pixbuf);
info->format = 1; // ANDROID_BITMAP_FORMAT_RGBA_8888
int AndroidBitmap_getInfo(JNIEnv* env, jobject bitmap, struct AndroidBitmapInfo *info)
{
info->width = _GET_INT_FIELD(bitmap, "width");
info->height = _GET_INT_FIELD(bitmap, "height");
info->stride = _GET_INT_FIELD(bitmap, "stride");
info->format = _GET_INT_FIELD(_GET_OBJ_FIELD(bitmap, "config", "Landroid/graphics/Bitmap$Config;"), "android_memory_format");
return ANDROID_BITMAP_RESULT_SUCCESS;
}
int AndroidBitmap_lockPixels(JNIEnv* env, jobject bitmap, void** pixels) {
GdkPixbuf *pixbuf = _PTR(_GET_LONG_FIELD(bitmap, "pixbuf"));
*pixels = gdk_pixbuf_get_pixels(pixbuf);
int AndroidBitmap_lockPixels(JNIEnv* env, jobject bitmap, void** pixels)
{
printf("AndroidBitmap_lockPixels\n");
GdkTexture *texture = _PTR((*env)->CallLongMethod(env, bitmap, _METHOD(_CLASS(bitmap), "getTexture", "()J")));
int stride = _GET_INT_FIELD(bitmap, "stride");
int format = _GET_INT_FIELD(_GET_OBJ_FIELD(bitmap, "config", "Landroid/graphics/Bitmap$Config;"), "gdk_memory_format");
if (format == -1) {
printf("AndroidBitmap_lockPixels: format not implemented\n");
exit(1);
}
GdkTextureDownloader *downloader = gdk_texture_downloader_new(texture);
gdk_texture_downloader_set_format(downloader, format);
GBytes *bytes = NULL;
if (GDK_IS_MEMORY_TEXTURE(texture)) { // try to get the bytes non-copying
gsize texture_stride;
bytes = gdk_texture_downloader_download_bytes(downloader, &texture_stride);
if (texture_stride != stride) { // texture was not created by us, fall back to copy
g_bytes_unref(bytes);
bytes = NULL;
}
}
if (bytes == NULL) {
guchar *data = g_malloc(stride * gdk_texture_get_height(texture));
gdk_texture_downloader_download_into(downloader, data, stride);
bytes = g_bytes_new_take(data, stride * gdk_texture_get_height(texture));
}
gdk_texture_downloader_free(downloader);
_SET_LONG_FIELD(bitmap, "bytes", _INTPTR(bytes));
*pixels = (void *)g_bytes_get_data(bytes, NULL);
return ANDROID_BITMAP_RESULT_SUCCESS;
}
int AndroidBitmap_unlockPixels(JNIEnv* env, jobject bitmap) {
int AndroidBitmap_unlockPixels(JNIEnv* env, jobject bitmap)
{
printf("AndroidBitmap_unlockPixels\n");
GBytes *bytes = _PTR(_GET_LONG_FIELD(bitmap, "bytes"));
if (!bytes) {
printf("AndroidBitmap_unlockPixels: no bytes! Was AndroidBitmap_lockPixels called?\n");
exit(1);
}
int width = _GET_INT_FIELD(bitmap, "width");
int height = _GET_INT_FIELD(bitmap, "height");
int stride = _GET_INT_FIELD(bitmap, "stride");
int format = _GET_INT_FIELD(_GET_OBJ_FIELD(bitmap, "config", "Landroid/graphics/Bitmap$Config;"), "gdk_memory_format");
if (format == -1) {
printf("AndroidBitmap_lockPixels: format not implemented\n");
exit(1);
}
GdkTexture *texture = gdk_memory_texture_new(width, height, format, bytes, stride);
g_bytes_unref(bytes);
(*env)->CallVoidMethod(env, bitmap, _METHOD(_CLASS(bitmap), "recycle", "()V"));
_SET_LONG_FIELD(bitmap, "texture", _INTPTR(texture));
_SET_LONG_FIELD(bitmap, "bytes", 0);
return ANDROID_BITMAP_RESULT_SUCCESS;
}