diff --git a/imgui.h b/imgui.h index f361102c..47f15fb1 100644 --- a/imgui.h +++ b/imgui.h @@ -2323,7 +2323,7 @@ struct ImFontAtlas // [Internal] Packing data int PackIdMouseCursors; // Custom texture rectangle ID for white pixel and mouse cursors - ImVector AALineRectIds; // Custom texture rectangle IDs for anti-aliased lines + int AALineRectId; // Custom texture rectangle ID for anti-aliased lines ImVector TexUvAALines; // UVs for anti-aliased line textures #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS diff --git a/imgui_draw.cpp b/imgui_draw.cpp index 41d25955..376d4141 100644 --- a/imgui_draw.cpp +++ b/imgui_draw.cpp @@ -677,11 +677,12 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32 const float AA_SIZE = 1.0f; const ImU32 col_trans = col & ~IM_COL32_A_MASK; - // The -0.5f here is to better match the geometry-based code, and also shift the transition point from one width texture to another off the integer values (where it will be less noticeable) - const int integer_thickness = ImMax((int)(thickness - 0.5f), 1); + // The thick_line test is an attempt to compensate for the way half_draw_size gets calculated later, which special-cases 1.0f width lines + const int integer_thickness = thick_line ? ImMax((int)(thickness), 1) : 2; + const float fractional_thickness = thick_line ? (thickness) - integer_thickness : 0.0f; // Do we want to draw this line using a texture? - const bool use_texture = (Flags & ImDrawListFlags_AntiAliasedLinesUseTexData) && (integer_thickness <= IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX); + const bool use_texture = (Flags & ImDrawListFlags_AntiAliasedLinesUseTexData) && (integer_thickness < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX); // We should never hit this, because NewFrame() doesn't set ImDrawListFlags_AntiAliasedLinesUseTexData unless ImFontAtlasFlags_NoAALines is off IM_ASSERT_PARANOID((!use_texture) || (!(_Data->Font->ContainerAtlas->Flags & ImFontAtlasFlags_NoAALines))); @@ -711,8 +712,9 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32 // If we are drawing a one-pixel-wide line without a texture, or a textured line of any width, we only need 2 or 3 vertices per point if (!thick_line || use_texture) { - // The width of the geometry we need to draw - const float half_draw_size = (!thick_line) ? AA_SIZE : (AA_SIZE + (thickness * 0.5f)); + // The width of the geometry we need to draw - this is essentially pixels for the line itself, plus one pixel for AA + // We don't use AA_SIZE here because the +1 is tied to the generated texture and so alternate values won't work without changes to that code + const float half_draw_size = (thickness * 0.5f) + 1; // If line is not closed, the first and last points need to be generated differently as there are no normals to blend if (!closed) @@ -770,7 +772,18 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32 if (use_texture) { // If we're using textures we only need to emit the left/right edge vertices - const ImVec4 tex_uvs = (*_Data->TexUvAALines)[integer_thickness - 1]; + + ImVec4 tex_uvs; + + if (fractional_thickness == 0.0f) // Fast path for pure integer widths + tex_uvs = (*_Data->TexUvAALines)[integer_thickness]; + else + { + // Calculate UV by interpolating between the two nearest integer line widths + const ImVec4 tex_uvs_0 = (*_Data->TexUvAALines)[integer_thickness]; + const ImVec4 tex_uvs_1 = (*_Data->TexUvAALines)[integer_thickness + 1]; + tex_uvs = ImLerp(tex_uvs_0, tex_uvs_1, fractional_thickness); + } for (int i = 0; i < points_count; i++) { @@ -2373,24 +2386,14 @@ static void ImFontAtlasBuildRenderDefaultTexData(ImFontAtlas* atlas) atlas->TexUvWhitePixel = ImVec2((r->X + 0.5f) * atlas->TexUvScale.x, (r->Y + 0.5f) * atlas->TexUvScale.y); } -// This is called/shared by both the stb_truetype and the FreeType builder. -const unsigned int FONT_ATLAS_AA_LINE_TEX_HEIGHT = 1; // Technically we only need 1 pixel in the ideal case but this can be increased if necessary to give a border to avoid sampling artifacts - static void ImFontAtlasBuildRegisterAALineCustomRects(ImFontAtlas* atlas) { - if (atlas->AALineRectIds.Size > 0) - return; - if ((atlas->Flags & ImFontAtlasFlags_NoAALines)) return; - for (int n = 0; n < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX; n++) - { - // The "width + 3" here is interesting. +2 is to give space for the end caps, but the remaining +1 is - // because (empirically) to match the behavior of the untextured render path we need to draw lines one pixel wider. - const int width = n + 1; // The line width this entry corresponds to - atlas->AALineRectIds.push_back(atlas->AddCustomRectRegular(width + 3, FONT_ATLAS_AA_LINE_TEX_HEIGHT)); - } + const int max_width = IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX; // The maximum line width we want to generate + // The "max_width + 2" here is to give space for the end caps, whilst height (IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX+1) is to accommodate the fact we have a zero-width row + atlas->AALineRectId = atlas->AddCustomRectRegular(max_width + 2, IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX + 1); } static void ImFontAtlasBuildRenderAALinesTexData(ImFontAtlas* atlas) @@ -2401,27 +2404,42 @@ static void ImFontAtlasBuildRenderAALinesTexData(ImFontAtlas* atlas) if (atlas->Flags & ImFontAtlasFlags_NoAALines) return; - const int w = atlas->TexWidth; - for (unsigned int n = 0; n < IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX; n++) - { - IM_ASSERT(atlas->AALineRectIds.Size > (int)n); - ImFontAtlasCustomRect& r = atlas->CustomRects[atlas->AALineRectIds[n]]; - IM_ASSERT(r.IsPacked()); + ImFontAtlasCustomRect& r = atlas->CustomRects[atlas->AALineRectId]; + IM_ASSERT(r.IsPacked()); - // We fill as many lines as we were given, to allow for >1 lines being used to work around sampling weirdness - for (unsigned int y = 0; y < r.Height; y++) - { - // Each line consists of two empty pixels at the ends, with a line of solid pixels in the middle - unsigned char* write_ptr = &atlas->TexPixelsAlpha8[r.X + ((r.Y + y) * w)]; + // This generates a triangular shape in the texture, with the various line widths stacked on top of each other to allow interpolation between them + const int w = atlas->TexWidth; + for (unsigned int n = 0; n < (IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX + 1); n++) // +1 because of the zero-width row + { + unsigned int y = n; + unsigned int line_width = n; + // Each line consists of at least two empty pixels at the ends, with a line of solid pixels in the middle + unsigned int pad_left = (r.Width - line_width) / 2; + unsigned int pad_right = r.Width - (pad_left + line_width); + + // Make sure we're inside the texture bounds before we start writing pixels + IM_ASSERT_PARANOID(pad_left + line_width + pad_right == r.Width); + IM_ASSERT_PARANOID(y < r.Height); + + // Write each slice + unsigned char* write_ptr = &atlas->TexPixelsAlpha8[r.X + ((r.Y + y) * w)]; + for (unsigned int x = 0; x < pad_left; x++) *(write_ptr++) = 0; - for (unsigned short x = 0; x < (r.Width - 2U); x++) - *(write_ptr++) = 0xFF; + for (unsigned int x = 0; x < line_width; x++) + *(write_ptr++) = 0xFF; + for (unsigned int x = 0; x < pad_right; x++) *(write_ptr++) = 0; - } + + // Calculate UVs for this line + ImFontAtlasCustomRect line_rect = r; + line_rect.X += (unsigned short)(pad_left - 1); + line_rect.Width = (unsigned short)(line_width + 2); + line_rect.Y += (unsigned short)y; + line_rect.Height = 1; ImVec2 uv0, uv1; - atlas->CalcCustomRectUV(&r, &uv0, &uv1); - float halfV = (uv0.y + uv1.y) * 0.5f; // Calculate a constant V in the middle of the texture as we want a horizontal slice (with some padding either side to avoid sampling artifacts) + atlas->CalcCustomRectUV(&line_rect, &uv0, &uv1); + float halfV = (uv0.y + uv1.y) * 0.5f; // Calculate a constant V in the middle of the row to avoid sampling artifacts atlas->TexUvAALines.push_back(ImVec4(uv0.x, halfV, uv1.x, halfV)); } } diff --git a/imgui_internal.h b/imgui_internal.h index d38d9b78..4f3882c9 100644 --- a/imgui_internal.h +++ b/imgui_internal.h @@ -529,7 +529,7 @@ struct IMGUI_API ImChunkStream #define IM_DRAWLIST_ARCFAST_TESSELLATION_MULTIPLIER 1 #endif -// The maximum line width to build anti-aliased textures for +// The maximum line width to build anti-aliased textures for (note that this needs to be one greater than the maximum line width you want to be able to draw using the textured path) #define IM_DRAWLIST_TEX_AA_LINES_WIDTH_MAX 65 // Data shared between all ImDrawList instances